diff --git a/lucene/src/java/org/apache/lucene/index/FieldInfos.java b/lucene/src/java/org/apache/lucene/index/FieldInfos.java
index 8e12ef5e864..4a962b6e289 100644
--- a/lucene/src/java/org/apache/lucene/index/FieldInfos.java
+++ b/lucene/src/java/org/apache/lucene/index/FieldInfos.java
@@ -407,7 +407,7 @@ public final class FieldInfos implements Iterable<FieldInfo> {
 
   public boolean hasNorms() {
     for (FieldInfo fi : this) {
-      if (!fi.omitNorms) {
+      if (fi.isIndexed && !fi.omitNorms) {
         return true;
       }
     }
diff --git a/lucene/src/java/org/apache/lucene/index/SegmentMerger.java b/lucene/src/java/org/apache/lucene/index/SegmentMerger.java
index 0940d8e63eb..cfb7301ded9 100644
--- a/lucene/src/java/org/apache/lucene/index/SegmentMerger.java
+++ b/lucene/src/java/org/apache/lucene/index/SegmentMerger.java
@@ -19,7 +19,6 @@ package org.apache.lucene.index;
 
 import java.io.IOException;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 
@@ -28,13 +27,12 @@ import org.apache.lucene.index.IndexReader.FieldOption;
 import org.apache.lucene.index.codecs.Codec;
 import org.apache.lucene.index.codecs.FieldInfosWriter;
 import org.apache.lucene.index.codecs.FieldsConsumer;
+import org.apache.lucene.index.codecs.NormsWriter;
 import org.apache.lucene.index.codecs.StoredFieldsWriter;
 import org.apache.lucene.index.codecs.PerDocConsumer;
 import org.apache.lucene.index.codecs.TermVectorsWriter;
-import org.apache.lucene.index.codecs.lucene40.Lucene40NormsWriter;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.IOContext;
-import org.apache.lucene.store.IndexOutput;
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.IOUtils;
 import org.apache.lucene.util.InfoStream;
@@ -122,7 +120,11 @@ final class SegmentMerger {
     final SegmentWriteState segmentWriteState = new SegmentWriteState(mergeState.infoStream, directory, segment, mergeState.fieldInfos, mergeState.mergedDocCount, termIndexInterval, codec, null, context);
     mergeTerms(segmentWriteState);
     mergePerDoc(segmentWriteState);
-    mergeNorms();
+    
+    if (mergeState.fieldInfos.hasNorms()) {
+      int numMerged = mergeNorms(segmentWriteState);
+      assert numMerged == mergeState.mergedDocCount;
+    }
 
     if (mergeState.fieldInfos.hasVectors()) {
       int numMerged = mergeVectors();
@@ -325,49 +327,19 @@ final class SegmentMerger {
       }
   }
 
-  // TODO: implement merge in normsformat instead.
-  private void mergeNorms() throws IOException {
-    IndexOutput output = null;
+  private int mergeNorms(SegmentWriteState segmentWriteState) throws IOException {
+    final NormsWriter writer = codec.normsFormat().normsWriter(segmentWriteState);
+    
     boolean success = false;
     try {
-      for (FieldInfo fi : mergeState.fieldInfos) {
-        if (fi.isIndexed && !fi.omitNorms) {
-          if (output == null) {
-            output = directory.createOutput(IndexFileNames.segmentFileName(segment, "", IndexFileNames.NORMS_EXTENSION), context);
-            output.writeBytes(Lucene40NormsWriter.NORMS_HEADER, Lucene40NormsWriter.NORMS_HEADER.length);
-          }
-          for (MergeState.IndexReaderAndLiveDocs reader : mergeState.readers) {
-            final int maxDoc = reader.reader.maxDoc();
-            byte normBuffer[] = reader.reader.norms(fi.name);
-            if (normBuffer == null) {
-              // Can be null if this segment doesn't have
-              // any docs with this field
-              normBuffer = new byte[maxDoc];
-              Arrays.fill(normBuffer, (byte)0);
-            }
-            if (reader.liveDocs == null) {
-              //optimized case for segments without deleted docs
-              output.writeBytes(normBuffer, maxDoc);
-            } else {
-              // this segment has deleted docs, so we have to
-              // check for every doc if it is deleted or not
-              final Bits liveDocs = reader.liveDocs;
-              for (int k = 0; k < maxDoc; k++) {
-                if (liveDocs.get(k)) {
-                  output.writeByte(normBuffer[k]);
-                }
-              }
-            }
-            mergeState.checkAbort.work(maxDoc);
-          }
-        }
-      }
+      int numMerged = writer.merge(mergeState);
       success = true;
+      return numMerged;
     } finally {
       if (success) {
-        IOUtils.close(output);
+        IOUtils.close(writer);
       } else {
-        IOUtils.closeWhileHandlingException(output);
+        IOUtils.closeWhileHandlingException(writer);
       }
     }
   }
diff --git a/lucene/src/java/org/apache/lucene/index/codecs/NormsWriter.java b/lucene/src/java/org/apache/lucene/index/codecs/NormsWriter.java
index 2be8db57a70..aa1e5b55dfb 100644
--- a/lucene/src/java/org/apache/lucene/index/codecs/NormsWriter.java
+++ b/lucene/src/java/org/apache/lucene/index/codecs/NormsWriter.java
@@ -19,8 +19,11 @@ package org.apache.lucene.index.codecs;
 
 import java.io.Closeable;
 import java.io.IOException;
+import java.util.Arrays;
 
 import org.apache.lucene.index.FieldInfo;
+import org.apache.lucene.index.MergeState;
+import org.apache.lucene.util.Bits;
 
 // simple api just for now before switching to docvalues apis
 public abstract class NormsWriter implements Closeable {
@@ -31,4 +34,37 @@ public abstract class NormsWriter implements Closeable {
   public abstract void writeNorm(byte norm) throws IOException;
   public abstract void finish(int numDocs) throws IOException;
   
+  public int merge(MergeState mergeState) throws IOException {
+    int numMergedDocs = 0;
+    for (FieldInfo fi : mergeState.fieldInfos) {
+      if (fi.isIndexed && !fi.omitNorms) {
+        startField(fi);
+        int numMergedDocsForField = 0;
+        for (MergeState.IndexReaderAndLiveDocs reader : mergeState.readers) {
+          final int maxDoc = reader.reader.maxDoc();
+          byte normBuffer[] = reader.reader.norms(fi.name);
+          if (normBuffer == null) {
+            // Can be null if this segment doesn't have
+            // any docs with this field
+            normBuffer = new byte[maxDoc];
+            Arrays.fill(normBuffer, (byte)0);
+          }
+          // this segment has deleted docs, so we have to
+          // check for every doc if it is deleted or not
+          final Bits liveDocs = reader.liveDocs;
+          for (int k = 0; k < maxDoc; k++) {
+            if (liveDocs == null || liveDocs.get(k)) {
+              writeNorm(normBuffer[k]);
+              numMergedDocsForField++;
+            }
+          }
+          mergeState.checkAbort.work(maxDoc);
+        }
+        assert numMergedDocs == 0 || numMergedDocs == numMergedDocsForField;
+        numMergedDocs = numMergedDocsForField;
+      }
+    }
+    finish(numMergedDocs);
+    return numMergedDocs;
+  }
 }
diff --git a/lucene/src/java/org/apache/lucene/index/codecs/lucene40/Lucene40NormsWriter.java b/lucene/src/java/org/apache/lucene/index/codecs/lucene40/Lucene40NormsWriter.java
index ac693badbab..576b01626fc 100644
--- a/lucene/src/java/org/apache/lucene/index/codecs/lucene40/Lucene40NormsWriter.java
+++ b/lucene/src/java/org/apache/lucene/index/codecs/lucene40/Lucene40NormsWriter.java
@@ -18,13 +18,16 @@ package org.apache.lucene.index.codecs.lucene40;
  */
 
 import java.io.IOException;
+import java.util.Arrays;
 
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.IndexFileNames;
+import org.apache.lucene.index.MergeState;
 import org.apache.lucene.index.codecs.NormsWriter;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.IOContext;
 import org.apache.lucene.store.IndexOutput;
+import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.IOUtils;
 
 public class Lucene40NormsWriter extends NormsWriter {
@@ -66,6 +69,48 @@ public class Lucene40NormsWriter extends NormsWriter {
       throw new RuntimeException(".nrm file size mismatch: expected=" + (4+normCount*(long)numDocs) + " actual=" + out.getFilePointer());
     }
   }
+  
+  /** we override merge and bulk-merge norms when there are no deletions */
+  @Override
+  public int merge(MergeState mergeState) throws IOException {
+    int numMergedDocs = 0;
+    for (FieldInfo fi : mergeState.fieldInfos) {
+      if (fi.isIndexed && !fi.omitNorms) {
+        startField(fi);
+        int numMergedDocsForField = 0;
+        for (MergeState.IndexReaderAndLiveDocs reader : mergeState.readers) {
+          final int maxDoc = reader.reader.maxDoc();
+          byte normBuffer[] = reader.reader.norms(fi.name);
+          if (normBuffer == null) {
+            // Can be null if this segment doesn't have
+            // any docs with this field
+            normBuffer = new byte[maxDoc];
+            Arrays.fill(normBuffer, (byte)0);
+          }
+          if (reader.liveDocs == null) {
+            //optimized case for segments without deleted docs
+            out.writeBytes(normBuffer, maxDoc);
+            numMergedDocsForField += maxDoc;
+          } else {
+            // this segment has deleted docs, so we have to
+            // check for every doc if it is deleted or not
+            final Bits liveDocs = reader.liveDocs;
+            for (int k = 0; k < maxDoc; k++) {
+              if (liveDocs.get(k)) {
+                numMergedDocsForField++;
+                out.writeByte(normBuffer[k]);
+              }
+            }
+          }
+          mergeState.checkAbort.work(maxDoc);
+        }
+        assert numMergedDocs == 0 || numMergedDocs == numMergedDocsForField;
+        numMergedDocs = numMergedDocsForField;
+      }
+    }
+    finish(numMergedDocs);
+    return numMergedDocs;
+  }
 
   @Override
   public void close() throws IOException {