diff --git a/server/errors.json b/server/errors.json
index 7f04b23469a..410544bdaa2 100644
--- a/server/errors.json
+++ b/server/errors.json
@@ -1988,5 +1988,15 @@
     "help": "",
     "url": "",
     "deprecates": ""
+  },
+  {
+    "constant": "JSAtomicPublishContainsDuplicateMessageErr",
+    "code": 400,
+    "error_code": 10201,
+    "description": "atomic publish batch contains duplicate message id",
+    "comment": "",
+    "help": "",
+    "url": "",
+    "deprecates": ""
   }
 ]
diff --git a/server/jetstream_batching.go b/server/jetstream_batching.go
index 16daf30648a..fc97f1f5453 100644
--- a/server/jetstream_batching.go
+++ b/server/jetstream_batching.go
@@ -303,7 +303,7 @@ func checkMsgHeadersPreClusteredProposal(
 		if msgId := getMsgId(hdr); msgId != _EMPTY_ {
 			// Dedupe if staged.
 			if _, ok = diff.msgIds[msgId]; ok {
-				return hdr, msg, 0, nil, errMsgIdDuplicate
+				return hdr, msg, 0, NewJSAtomicPublishContainsDuplicateMessageError(), errMsgIdDuplicate
 			}
 			mset.ddMu.Lock()
 			if dde := mset.checkMsgId(msgId); dde != nil {
@@ -311,7 +311,7 @@ func checkMsgHeadersPreClusteredProposal(
 				mset.ddMu.Unlock()
 				// Should not return an invalid sequence, in that case error.
 				if seq > 0 {
-					return hdr, msg, seq, nil, errMsgIdDuplicate
+					return hdr, msg, seq, NewJSAtomicPublishContainsDuplicateMessageError(), errMsgIdDuplicate
 				} else {
 					return hdr, msg, 0, NewJSStreamDuplicateMessageConflictError(), errMsgIdDuplicate
 				}
diff --git a/server/jetstream_batching_test.go b/server/jetstream_batching_test.go
index c00d3c5fdf6..e64e958fc68 100644
--- a/server/jetstream_batching_test.go
+++ b/server/jetstream_batching_test.go
@@ -397,24 +397,38 @@ func TestJetStreamAtomicBatchPublishDedupeNotAllowed(t *testing.T) {
 		_, err := jsStreamCreate(t, nc, cfg)
 		require_NoError(t, err)
 
+		_, err = js.Publish("foo", nil, nats.MsgId("pre-existing"))
+		require_NoError(t, err)
+
+		var pubAck JSPubAckResponse
 		m := nats.NewMsg("foo")
+		m.Header.Set("Nats-Msg-Id", "pre-existing")
+		m.Header.Set("Nats-Batch-Id", "uuid")
+		m.Header.Set("Nats-Batch-Sequence", "1")
+		m.Header.Set("Nats-Batch-Commit", "1")
+		rmsg, err := nc.RequestMsg(m, time.Second)
+		require_NoError(t, err)
+		require_NoError(t, json.Unmarshal(rmsg.Data, &pubAck))
+		require_NotNil(t, pubAck.Error)
+		require_Error(t, pubAck.Error, NewJSAtomicPublishContainsDuplicateMessageError())
+
+		m = nats.NewMsg("foo")
 		m.Header.Set("Nats-Batch-Id", "uuid")
 		m.Header.Set("Nats-Batch-Sequence", "1")
 		m.Header.Set("Nats-Msg-Id", "msgId1")
 		require_NoError(t, nc.PublishMsg(m))
-		m.Header.Set("Nats-Batch-Sequence", "2")
-		m.Header.Set("Nats-Msg-Id", "pre-existing")
-		require_NoError(t, nc.PublishMsg(m))
 
-		var pubAck JSPubAckResponse
-		m.Header.Set("Nats-Batch-Sequence", "3")
+		pubAck = JSPubAckResponse{}
+		m.Header.Set("Nats-Batch-Sequence", "2")
 		m.Header.Set("Nats-Msg-Id", "msgId2")
 		m.Header.Set("Nats-Batch-Commit", "1")
-		rmsg, err := nc.RequestMsg(m, time.Second)
+		rmsg, err = nc.RequestMsg(m, time.Second)
 		require_NoError(t, err)
 		require_NoError(t, json.Unmarshal(rmsg.Data, &pubAck))
-		require_NotNil(t, pubAck.Error)
-		require_Error(t, pubAck.Error, NewJSAtomicPublishUnsupportedHeaderBatchError("Nats-Msg-Id"))
+		require_True(t, pubAck.Error == nil)
+		require_Equal(t, pubAck.BatchSize, 2)
+		require_Equal(t, pubAck.Sequence, 3)
+		require_Equal(t, pubAck.BatchId, "uuid")
 	}
 
 	for _, storage := range []StorageType{FileStorage, MemoryStorage} {
@@ -727,7 +741,6 @@ func TestJetStreamAtomicBatchPublishDenyHeaders(t *testing.T) {
 
 		// We might support these headers later on, but for now error.
 		for key, value := range map[string]string{
-			"Nats-Msg-Id":               "msgId",
 			"Nats-Expected-Last-Msg-Id": "msgId",
 		} {
 			t.Run(key, func(t *testing.T) {
diff --git a/server/jetstream_errors_generated.go b/server/jetstream_errors_generated.go
index dbc7f0499d7..d244ebd7ac2 100644
--- a/server/jetstream_errors_generated.go
+++ b/server/jetstream_errors_generated.go
@@ -8,6 +8,9 @@ const (
 	// JSAccountResourcesExceededErr resource limits exceeded for account
 	JSAccountResourcesExceededErr ErrorIdentifier = 10002
 
+	// JSAtomicPublishContainsDuplicateMessageErr atomic publish batch contains duplicate message id
+	JSAtomicPublishContainsDuplicateMessageErr ErrorIdentifier = 10201
+
 	// JSAtomicPublishDisabledErr atomic publish is disabled
 	JSAtomicPublishDisabledErr ErrorIdentifier = 10174
 
@@ -606,6 +609,7 @@ const (
 var (
 	ApiErrors = map[ErrorIdentifier]*ApiError{
 		JSAccountResourcesExceededErr:                {Code: 400, ErrCode: 10002, Description: "resource limits exceeded for account"},
+		JSAtomicPublishContainsDuplicateMessageErr:   {Code: 400, ErrCode: 10201, Description: "atomic publish batch contains duplicate message id"},
 		JSAtomicPublishDisabledErr:                   {Code: 400, ErrCode: 10174, Description: "atomic publish is disabled"},
 		JSAtomicPublishIncompleteBatchErr:            {Code: 400, ErrCode: 10176, Description: "atomic publish batch is incomplete"},
 		JSAtomicPublishInvalidBatchCommitErr:         {Code: 400, ErrCode: 10200, Description: "atomic publish batch commit is invalid"},
@@ -839,6 +843,16 @@ func NewJSAccountResourcesExceededError(opts ...ErrorOption) *ApiError {
 	return ApiErrors[JSAccountResourcesExceededErr]
 }
 
+// NewJSAtomicPublishContainsDuplicateMessageError creates a new JSAtomicPublishContainsDuplicateMessageErr error: "atomic publish batch contains duplicate message id"
+func NewJSAtomicPublishContainsDuplicateMessageError(opts ...ErrorOption) *ApiError {
+	eopts := parseOpts(opts)
+	if ae, ok := eopts.err.(*ApiError); ok {
+		return ae
+	}
+
+	return ApiErrors[JSAtomicPublishContainsDuplicateMessageErr]
+}
+
 // NewJSAtomicPublishDisabledError creates a new JSAtomicPublishDisabledErr error: "atomic publish is disabled"
 func NewJSAtomicPublishDisabledError(opts ...ErrorOption) *ApiError {
 	eopts := parseOpts(opts)
diff --git a/server/stream.go b/server/stream.go
index 1bf64daba42..50c4a1b0778 100644
--- a/server/stream.go
+++ b/server/stream.go
@@ -6505,9 +6505,6 @@ func (mset *stream) processJetStreamBatchMsg(batchId, subject, reply string, hdr
 		}
 
 		// Reject unsupported headers.
-		if msgId := getMsgId(bhdr); msgId != _EMPTY_ {
-			return errorOnUnsupported(seq, JSMsgId)
-		}
 		if getExpectedLastMsgId(hdr) != _EMPTY_ {
 			return errorOnUnsupported(seq, JSExpectedLastMsgId)
 		}