diff --git a/e2e/infrastructure/BlockHttp.spec.ts b/e2e/infrastructure/BlockHttp.spec.ts
index f87504ef83..9b721000ba 100644
--- a/e2e/infrastructure/BlockHttp.spec.ts
+++ b/e2e/infrastructure/BlockHttp.spec.ts
@@ -28,6 +28,7 @@ import { Deadline } from '../../src/model/transaction/Deadline';
 import { TransactionInfo } from '../../src/model/transaction/TransactionInfo';
 import { TransferTransaction } from '../../src/model/transaction/TransferTransaction';
 import { IntegrationTestHelper } from './IntegrationTestHelper';
+import { UInt64 } from '../../src/model/UInt64';
 
 describe('BlockHttp', () => {
     const helper = new IntegrationTestHelper();
@@ -87,7 +88,7 @@ describe('BlockHttp', () => {
 
     describe('getBlockByHeight', () => {
         it('should return block info given height', (done) => {
-            blockRepository.getBlockByHeight('1')
+            blockRepository.getBlockByHeight(UInt64.fromUint(1))
             .subscribe((blockInfo) => {
                 blockReceiptHash = blockInfo.blockReceiptsHash;
                 blockTransactionHash = blockInfo.blockTransactionsHash;
@@ -105,7 +106,7 @@ describe('BlockHttp', () => {
         let firstId: string;
 
         it('should return block transactions data given height', (done) => {
-            blockRepository.getBlockTransactions('1')
+            blockRepository.getBlockTransactions(UInt64.fromUint(1))
             .subscribe((transactions) => {
                 nextId = transactions[0].transactionInfo!.id;
                 firstId = transactions[1].transactionInfo!.id;
@@ -115,7 +116,7 @@ describe('BlockHttp', () => {
         });
 
         it('should return block transactions data given height with paginated transactionId', (done) => {
-            blockRepository.getBlockTransactions('1', new QueryParams(10, nextId))
+            blockRepository.getBlockTransactions(UInt64.fromUint(1), new QueryParams(10, nextId))
             .subscribe((transactions) => {
                 expect(transactions[0].transactionInfo!.id).to.be.equal(firstId);
                 expect(transactions.length).to.be.greaterThan(0);
diff --git a/src/infrastructure/BlockHttp.ts b/src/infrastructure/BlockHttp.ts
index 597e9e73ed..c30b03939c 100644
--- a/src/infrastructure/BlockHttp.ts
+++ b/src/infrastructure/BlockHttp.ts
@@ -54,8 +54,8 @@ export class BlockHttp extends Http implements BlockRepository {
      * @param height - Block height
      * @returns Observable<BlockInfo>
      */
-    public getBlockByHeight(height: string): Observable<BlockInfo> {
-        return observableFrom(this.blockRoutesApi.getBlockByHeight(height)).pipe(
+    public getBlockByHeight(height: UInt64): Observable<BlockInfo> {
+        return observableFrom(this.blockRoutesApi.getBlockByHeight(height.toString())).pipe(
             map(({body}) => this.toBlockInfo(body)),
             catchError((error) =>  throwError(this.errorHandling(error))),
         );
@@ -67,10 +67,10 @@ export class BlockHttp extends Http implements BlockRepository {
      * @param queryParams - (Optional) Query params
      * @returns Observable<Transaction[]>
      */
-    public getBlockTransactions(height: string,
+    public getBlockTransactions(height: UInt64,
                                 queryParams?: QueryParams): Observable<Transaction[]> {
         return observableFrom(
-            this.blockRoutesApi.getBlockTransactions(height,
+            this.blockRoutesApi.getBlockTransactions(height.toString(),
                                                      this.queryParams(queryParams).pageSize,
                                                      this.queryParams(queryParams).id,
                                                      this.queryParams(queryParams).order))
@@ -87,9 +87,9 @@ export class BlockHttp extends Http implements BlockRepository {
      * @param limit - Number of blocks returned.
      * @returns Observable<BlockInfo[]>
      */
-    public getBlocksByHeightWithLimit(height: string, limit: number): Observable<BlockInfo[]> {
+    public getBlocksByHeightWithLimit(height: UInt64, limit: number): Observable<BlockInfo[]> {
         return observableFrom(
-            this.blockRoutesApi.getBlocksByHeightWithLimit(height, limit)).pipe(
+            this.blockRoutesApi.getBlocksByHeightWithLimit(height.toString(), limit)).pipe(
                 map(({body}) => body.map((blockDTO) => this.toBlockInfo(blockDTO))),
                 catchError((error) =>  throwError(this.errorHandling(error))),
         );
@@ -136,9 +136,9 @@ export class BlockHttp extends Http implements BlockRepository {
      * @param hash The hash of the transaction.
      * @return Observable<MerkleProofInfo>
      */
-    public getMerkleTransaction(height: string, hash: string): Observable<MerkleProofInfo> {
+    public getMerkleTransaction(height: UInt64, hash: string): Observable<MerkleProofInfo> {
         return observableFrom(
-            this.blockRoutesApi.getMerkleTransaction(height, hash)).pipe(
+            this.blockRoutesApi.getMerkleTransaction(height.toString(), hash)).pipe(
                 map(({body}) => new MerkleProofInfo(
                         body.merklePath!.map((payload) => new MerklePathItem(payload.position, payload.hash)),
                     )),
diff --git a/src/infrastructure/BlockRepository.ts b/src/infrastructure/BlockRepository.ts
index cd606ef22a..c4c6d97af1 100644
--- a/src/infrastructure/BlockRepository.ts
+++ b/src/infrastructure/BlockRepository.ts
@@ -17,8 +17,8 @@
 import {Observable} from 'rxjs';
 import {BlockInfo} from '../model/blockchain/BlockInfo';
 import { MerkleProofInfo } from '../model/blockchain/MerkleProofInfo';
-import { Statement } from '../model/receipt/Statement';
 import {Transaction} from '../model/transaction/Transaction';
+import { UInt64 } from '../model/UInt64';
 import {QueryParams} from './QueryParams';
 
 /**
@@ -33,7 +33,7 @@ export interface BlockRepository {
      * @param height - Block height
      * @returns Observable<BlockInfo>
      */
-    getBlockByHeight(height: string): Observable<BlockInfo>;
+    getBlockByHeight(height: UInt64): Observable<BlockInfo>;
 
     /**
      * Gets array of transactions included in a block for a block height
@@ -41,7 +41,7 @@ export interface BlockRepository {
      * @param queryParams - (Optional) Query params
      * @returns Observable<Transaction[]>
      */
-    getBlockTransactions(height: string,
+    getBlockTransactions(height: UInt64,
                          queryParams?: QueryParams): Observable<Transaction[]>;
 
     /**
@@ -51,7 +51,7 @@ export interface BlockRepository {
      * @returns Observable<BlockInfo[]>
      */
 
-    getBlocksByHeightWithLimit(height: string, limit: number): Observable<BlockInfo[]>;
+    getBlocksByHeightWithLimit(height: UInt64, limit: number): Observable<BlockInfo[]>;
 
     /**
      * Get the merkle path for a given a transaction and block
@@ -63,5 +63,5 @@ export interface BlockRepository {
      * @param hash The hash of the transaction.
      * @return Observable<MerkleProofInfo>
      */
-    getMerkleTransaction(height: string, hash: string): Observable<MerkleProofInfo>;
+    getMerkleTransaction(height: UInt64, hash: string): Observable<MerkleProofInfo>;
 }
diff --git a/src/infrastructure/ReceiptHttp.ts b/src/infrastructure/ReceiptHttp.ts
index 95ae940ae7..dad400a03a 100644
--- a/src/infrastructure/ReceiptHttp.ts
+++ b/src/infrastructure/ReceiptHttp.ts
@@ -21,6 +21,7 @@ import { MerklePathItem } from '../model/blockchain/MerklePathItem';
 import { MerkleProofInfo } from '../model/blockchain/MerkleProofInfo';
 import { NetworkType } from '../model/blockchain/NetworkType';
 import { Statement } from '../model/receipt/Statement';
+import { UInt64 } from '../model/UInt64';
 import { Http } from './Http';
 import { CreateStatementFromDTO } from './receipt/CreateReceiptFromDTO';
 import { ReceiptRepository } from './ReceiptRepository';
@@ -64,9 +65,9 @@ export class ReceiptHttp extends Http implements ReceiptRepository {
      * @param hash The hash of the receipt statement or resolution.
      * @return Observable<MerkleProofInfo>
      */
-    public getMerkleReceipts(height: string, hash: string): Observable<MerkleProofInfo> {
+    public getMerkleReceipts(height: UInt64, hash: string): Observable<MerkleProofInfo> {
         return observableFrom(
-            this.receiptRoutesApi.getMerkleReceipts(height, hash)).pipe(
+            this.receiptRoutesApi.getMerkleReceipts(height.toString(), hash)).pipe(
                 map(({body}) => new MerkleProofInfo(
                         body.merklePath!.map(
                             (payload) => new MerklePathItem(payload.position, payload.hash)),
@@ -81,10 +82,10 @@ export class ReceiptHttp extends Http implements ReceiptRepository {
      * @param queryParams - (Optional) Query params
      * @returns Observable<Statement>
      */
-    public getBlockReceipts(height: string): Observable<Statement> {
+    public getBlockReceipts(height: UInt64): Observable<Statement> {
         return this.networkTypeObservable.pipe(
             mergeMap((networkType) => observableFrom(
-                this.receiptRoutesApi.getBlockReceipts(height)).pipe(
+                this.receiptRoutesApi.getBlockReceipts(height.toString())).pipe(
                     map(({body}) => CreateStatementFromDTO(body, networkType)),
                     catchError((error) =>  throwError(this.errorHandling(error))),
                 ),
diff --git a/src/infrastructure/ReceiptRepository.ts b/src/infrastructure/ReceiptRepository.ts
index a9e98df384..4c0660a63f 100644
--- a/src/infrastructure/ReceiptRepository.ts
+++ b/src/infrastructure/ReceiptRepository.ts
@@ -17,6 +17,7 @@
 import {Observable} from 'rxjs';
 import { MerkleProofInfo } from '../model/blockchain/MerkleProofInfo';
 import { Statement } from '../model/receipt/Statement';
+import { UInt64 } from '../model/UInt64';
 
 /**
  * Receipt interface repository.
@@ -28,10 +29,10 @@ export interface ReceiptRepository {
     /**
      * Get receipts from a block
      * Returns the receipts linked to a block.
-     * @param {string} height The height of the block.
+     * @param {UInt64} height The height of the block.
      * @return Observable<Statement>
      */
-    getBlockReceipts(height: string): Observable<Statement>;
+    getBlockReceipts(height: UInt64): Observable<Statement>;
 
     /**
      * Get the merkle path for a given a receipt statement hash and block
@@ -43,5 +44,5 @@ export interface ReceiptRepository {
      * @param hash The hash of the receipt statement or resolution.
      * @return Observable<MerkleProofInfo>
      */
-    getMerkleReceipts(height: string, hash: string): Observable<MerkleProofInfo>;
+    getMerkleReceipts(height: UInt64, hash: string): Observable<MerkleProofInfo>;
 }
diff --git a/src/infrastructure/RepositoryFactoryHttp.ts b/src/infrastructure/RepositoryFactoryHttp.ts
index 85357ed5d0..1bd08e7783 100644
--- a/src/infrastructure/RepositoryFactoryHttp.ts
+++ b/src/infrastructure/RepositoryFactoryHttp.ts
@@ -17,6 +17,7 @@
 import { Observable, of as observableOf } from 'rxjs';
 import { map, share, shareReplay } from 'rxjs/operators';
 import { NetworkType } from '../model/blockchain/NetworkType';
+import { UInt64 } from '../model/UInt64';
 import { AccountHttp } from './AccountHttp';
 import { AccountRepository } from './AccountRepository';
 import { BlockHttp } from './BlockHttp';
@@ -69,7 +70,7 @@ export class RepositoryFactoryHttp implements RepositoryFactory {
         this.url = url;
         this.networkType = networkType ? observableOf(networkType) : this.createNetworkRepository().getNetworkType().pipe(shareReplay(1));
         this.generationHash = generationHash ? observableOf(generationHash) :
-            this.createBlockRepository().getBlockByHeight('1').pipe(map((b) => b.generationHash)).pipe(shareReplay(1));
+            this.createBlockRepository().getBlockByHeight(UInt64.fromUint(1)).pipe(map((b) => b.generationHash)).pipe(shareReplay(1));
     }
 
     createAccountRepository(): AccountRepository {
diff --git a/src/service/TransactionService.ts b/src/service/TransactionService.ts
index 902a77496f..fc2aa8da73 100644
--- a/src/service/TransactionService.ts
+++ b/src/service/TransactionService.ts
@@ -181,7 +181,7 @@ export class TransactionService implements ITransactionService {
      * @return {Observable<Transaction>}
      */
     private resolvedFromReceipt(transaction: Transaction, aggregateIndex: number): Observable<Transaction> {
-        return this.receiptRepository.getBlockReceipts(transaction.transactionInfo!.height.toString()).pipe(
+        return this.receiptRepository.getBlockReceipts(transaction.transactionInfo!.height).pipe(
             map((statement) => transaction.resolveAliases(statement, aggregateIndex)),
         );
     }
diff --git a/test/infrastructure/RepositoryFactory.spec.ts b/test/infrastructure/RepositoryFactory.spec.ts
index 5dfcbcfd05..e80f44bf9b 100644
--- a/test/infrastructure/RepositoryFactory.spec.ts
+++ b/test/infrastructure/RepositoryFactory.spec.ts
@@ -16,12 +16,13 @@
 import { expect } from 'chai';
 import { of as observableOf } from 'rxjs';
 import { map } from 'rxjs/operators';
-import { instance, mock, when } from 'ts-mockito';
+import { deepEqual, instance, mock, when } from 'ts-mockito';
 import { BlockRepository } from '../../src/infrastructure/BlockRepository';
 import { NetworkRepository } from '../../src/infrastructure/NetworkRepository';
 import { RepositoryFactoryHttp } from '../../src/infrastructure/RepositoryFactoryHttp';
 import { BlockInfo } from '../../src/model/blockchain/BlockInfo';
 import { NetworkType } from '../../src/model/blockchain/NetworkType';
+import { UInt64 } from '../../src/model/UInt64';
 
 describe('RepositoryFactory', () => {
     it('Should create repositories', () => {
@@ -52,7 +53,7 @@ describe('RepositoryFactory', () => {
             counter++;
             return v;
         }));
-        when(repositoryMock.getBlockByHeight('1')).thenReturn(observableOfBlockInfo);
+        when(repositoryMock.getBlockByHeight(deepEqual(UInt64.fromUint(1)))).thenReturn(observableOfBlockInfo);
         expect(observableOfBlockInfo).to.be.equals(observableOfBlockInfo);
         const repositoryFactory = new (class RepositoryFactoryHttpForTest extends RepositoryFactoryHttp {