diff --git a/substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/HeapChunkProvider.java b/substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/HeapChunkProvider.java
index 8ecfb4dfb037..71d45a158683 100644
--- a/substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/HeapChunkProvider.java
+++ b/substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/HeapChunkProvider.java
@@ -251,7 +251,8 @@ UnalignedHeader produceUnalignedChunk(UnsignedWord objectSize) {
         UnalignedHeapChunk.initialize(result, chunkSize);
         assert objectSize.belowOrEqual(HeapChunk.availableObjectMemory(result)) : "UnalignedHeapChunk insufficient for requested object";
 
-        if (HeapParameters.getZapProducedHeapChunks()) {
+        /* Avoid zapping if unaligned chunks are pre-zeroed. */
+        if (!CommittedMemoryProvider.get().areUnalignedChunksZeroed() && HeapParameters.getZapProducedHeapChunks()) {
             zap(result, HeapParameters.getProducedHeapChunkZapWord());
         }
         return result;