diff --git a/core/src/main/scala/kafka/admin/AdminUtils.scala b/core/src/main/scala/kafka/admin/AdminUtils.scala
index 94c5332..fc69275 100644
--- a/core/src/main/scala/kafka/admin/AdminUtils.scala
+++ b/core/src/main/scala/kafka/admin/AdminUtils.scala
@@ -108,7 +108,10 @@ object AdminUtils extends Logging {
     if (existingPartitionsReplicaList.size == 0)
       throw new AdminOperationException("The topic %s does not exist".format(topic))
 
-    val existingReplicaList = existingPartitionsReplicaList.head._2
+    val existingReplicaList = existingPartitionsReplicaList.find(p => p._1.partition == 0) match {
+      case None => throw new AdminOperationException("PartitionId should start from 0")
+      case Some(headPartitionReplica) => headPartitionReplica._2
+    }
     val partitionsToAdd = numPartitions - existingPartitionsReplicaList.size
     if (partitionsToAdd <= 0)
       throw new AdminOperationException("The number of partitions for a topic can only be increased")
@@ -116,7 +119,7 @@ object AdminUtils extends Logging {
     // create the new partition replication list
     val brokerList = ZkUtils.getSortedBrokerList(zkClient)
     val newPartitionReplicaList = if (replicaAssignmentStr == null || replicaAssignmentStr == "")
-      AdminUtils.assignReplicasToBrokers(brokerList, partitionsToAdd, existingReplicaList.size, existingReplicaList.head, existingPartitionsReplicaList.size)
+      AdminUtils.assignReplicasToBrokers(brokerList, partitionsToAdd, existingReplicaList.size, brokerList.indexOf(existingReplicaList.head), existingPartitionsReplicaList.size)
     else
       getManualReplicaAssignment(replicaAssignmentStr, brokerList.toSet, existingPartitionsReplicaList.size, checkBrokerAvailable)