diff --git a/WHATSNEW b/WHATSNEW
index eb8e560e5..1992b61be 100644
--- a/WHATSNEW
+++ b/WHATSNEW
@@ -127,6 +127,10 @@ Other changes:
 * <taskdef> can now define several tasks at once, reading the 
   name/classname pairs from a property file or resource.
 
+* <unzip/unjar/unwar> and <untar> now have an overwrite attribute that
+  defaults to true.  If set to false, files that are newer than the
+  files in the archive will not be replaced.
+
 Fixed bugs:
 -----------
 
diff --git a/docs/manual/CoreTasks/untar.html b/docs/manual/CoreTasks/untar.html
index 6f978c63a..ce08510a1 100644
--- a/docs/manual/CoreTasks/untar.html
+++ b/docs/manual/CoreTasks/untar.html
@@ -35,6 +35,13 @@ carried from tarfile.</p>
     <td valign="top">directory where to store the expanded files.</td>
     <td align="center" valign="top">Yes</td>
   </tr>
+  <tr>
+    <td valign="top">overwrite</td>
+    <td valign="top"> Overwrite files, even if they are newer than the
+      corresponding entries in the archive (true or false, default is
+      true).</td>
+    <td align="center" valign="top">No</td>
+  </tr>
 </table>
 <h3>Examples</h3>
 <blockquote>
diff --git a/docs/manual/CoreTasks/unzip.html b/docs/manual/CoreTasks/unzip.html
index 918acb7a1..dd7415bc1 100644
--- a/docs/manual/CoreTasks/unzip.html
+++ b/docs/manual/CoreTasks/unzip.html
@@ -30,6 +30,13 @@ carried from zipfile.</p>
     <td valign="top">directory where to store the expanded files.</td>
     <td align="center" valign="top">Yes</td>
   </tr>
+  <tr>
+    <td valign="top">overwrite</td>
+    <td valign="top">Overwrite files, even if they are newer than the
+      corresponding entries in the archive (true or false, default is
+      true).</td>
+    <td align="center" valign="top">No</td>
+  </tr>
 </table>
 <h3>Examples</h3>
 <blockquote>
diff --git a/src/main/org/apache/tools/ant/taskdefs/Expand.java b/src/main/org/apache/tools/ant/taskdefs/Expand.java
index d66f53ceb..0db5146a7 100644
--- a/src/main/org/apache/tools/ant/taskdefs/Expand.java
+++ b/src/main/org/apache/tools/ant/taskdefs/Expand.java
@@ -66,6 +66,8 @@ import java.util.zip.*;
 public class Expand extends MatchingTask {
     private File dest; // req
     private File source; // req
+
+    private boolean overwrite = true;
     
     /**
      * Do the work.
@@ -104,8 +106,6 @@ public class Expand extends MatchingTask {
         else {
             expandFile(touch, source, dest);
         }
-        
-
     }
 
     private void expandFile(Touch touch, File srcF, File dir) {
@@ -119,7 +119,15 @@ public class Expand extends MatchingTask {
             while ((ze = zis.getNextEntry()) != null) {
                 File f = new File(dir, project.translatePath(ze.getName()));
                 try {
-                    log("expand-file " + ze.getName() , Project.MSG_VERBOSE );
+                    if (!overwrite && f.exists() 
+                        && f.lastModified() >= ze.getTime()) {
+                        log("Skipping " + f + " as it is up-to-date",
+                            Project.MSG_DEBUG);
+                        continue;
+                    }
+                    
+                    log("expanding " + ze.getName() + " to "+ f, 
+                        Project.MSG_VERBOSE);
                     // create intermediary directories - sometimes zip don't add them
                     File dirF=new File(f.getParent());
                     dirF.mkdirs();
@@ -179,4 +187,13 @@ public class Expand extends MatchingTask {
     public void setSrc(File s) {
         this.source = s;
     }
+
+    /**
+     * Should we overwrite files in dest, even if they are newer than
+     * the corresponding entries in the archive?
+     */
+    public void setOverwrite(boolean b) {
+        overwrite = b;
+    }
+
 }
diff --git a/src/main/org/apache/tools/ant/taskdefs/Untar.java b/src/main/org/apache/tools/ant/taskdefs/Untar.java
index 59beecad4..980ea9f05 100644
--- a/src/main/org/apache/tools/ant/taskdefs/Untar.java
+++ b/src/main/org/apache/tools/ant/taskdefs/Untar.java
@@ -69,6 +69,8 @@ public class Untar extends Task {
     private File dest; // req
     private File source; // req
 
+    private boolean overwrite = true;
+    
     /**
      * Do the work.
      *
@@ -105,8 +107,15 @@ public class Untar extends Task {
             while ((te = tis.getNextEntry()) != null) {
                 try {
                     File f = new File(dir, project.translatePath(te.getName()));
-                    log("expand-file " + te.getName(), Project.MSG_VERBOSE );
-                    // create intermediary directories - sometimes tar don't add them
+                    if (!overwrite && f.exists() 
+                        && f.lastModified() >= te.getModTime().getTime()) {
+                        log("Skipping " + f + " as it is up-to-date",
+                            Project.MSG_DEBUG);
+                        continue;
+                    }
+                    
+                    log("expanding " + te.getName() + " to "+ f, 
+                        Project.MSG_VERBOSE);
                     File dirF=new File(f.getParent());
                     dirF.mkdirs();
 
@@ -166,4 +175,13 @@ public class Untar extends Task {
     public void setSrc(File s) {
         this.source = s;
     }
+
+    /**
+     * Should we overwrite files in dest, even if they are newer than
+     * the corresponding entries in the archive?
+     */
+    public void setOverwrite(boolean b) {
+        overwrite = b;
+    }
+
 }