diff --git a/core/pactbroker/src/main/kotlin/au/com/dius/pact/core/pactbroker/PactBrokerClient.kt b/core/pactbroker/src/main/kotlin/au/com/dius/pact/core/pactbroker/PactBrokerClient.kt
index 7d0b654278..e5a80fc273 100644
--- a/core/pactbroker/src/main/kotlin/au/com/dius/pact/core/pactbroker/PactBrokerClient.kt
+++ b/core/pactbroker/src/main/kotlin/au/com/dius/pact/core/pactbroker/PactBrokerClient.kt
@@ -68,7 +68,16 @@ data class ConsumerVersionSelector(
   val latest: Boolean = true,
   val consumer: String? = null
 ) {
-  fun toJson() = JsonValue.Object("tag" to Json.toJson(tag), "latest" to Json.toJson(latest))
+  fun toJson(): JsonValue {
+    val obj = JsonValue.Object("latest" to Json.toJson(latest))
+    if (tag.isNotEmpty()) {
+      obj.add("tag", Json.toJson(tag))
+    }
+    if (consumer.isNotEmpty()) {
+      obj.add("consumer", Json.toJson(consumer))
+    }
+    return obj
+  }
 }
 
 interface IPactBrokerClient {
diff --git a/core/pactbroker/src/test/groovy/au/com/dius/pact/core/pactbroker/ConsumerVersionSelectorSpec.groovy b/core/pactbroker/src/test/groovy/au/com/dius/pact/core/pactbroker/ConsumerVersionSelectorSpec.groovy
new file mode 100644
index 0000000000..1d474de179
--- /dev/null
+++ b/core/pactbroker/src/test/groovy/au/com/dius/pact/core/pactbroker/ConsumerVersionSelectorSpec.groovy
@@ -0,0 +1,21 @@
+package au.com.dius.pact.core.pactbroker
+
+import spock.lang.Specification
+import spock.lang.Unroll
+
+class ConsumerVersionSelectorSpec extends Specification {
+
+  @Unroll
+  def 'convert to JSON'() {
+    expect:
+    new ConsumerVersionSelector(tag, latest, consumer).toJson().serialise() == json
+
+    where:
+
+    tag  | latest | consumer | json
+    'A'  | true   | null     | '{"latest":true,"tag":"A"}'
+    'A'  | false  | null     | '{"latest":false,"tag":"A"}'
+    'A'  | false  | 'Bob'    | '{"consumer":"Bob","latest":false,"tag":"A"}'
+    null | false  | 'Bob'    | '{"consumer":"Bob","latest":false}'
+  }
+}