diff --git a/tests/qemu-iotests/check b/tests/qemu-iotests/check
index baeae80f96..1fa63193ba 100755
--- a/tests/qemu-iotests/check
+++ b/tests/qemu-iotests/check
@@ -296,9 +296,15 @@ do
             run_command="./$seq"
         fi
         export OUTPUT_DIR=$PWD
-        (cd "$source_iotests";
-        MALLOC_PERTURB_=${MALLOC_PERTURB_:-$(($RANDOM % 255 + 1))} \
-                $run_command >$tmp.out 2>&1)
+        if $debug; then
+            (cd "$source_iotests";
+            MALLOC_PERTURB_=${MALLOC_PERTURB_:-$(($RANDOM % 255 + 1))} \
+                    $run_command -d 2>&1 | tee $tmp.out)
+        else
+            (cd "$source_iotests";
+            MALLOC_PERTURB_=${MALLOC_PERTURB_:-$(($RANDOM % 255 + 1))} \
+                    $run_command >$tmp.out 2>&1)
+        fi
         sts=$?
         $timestamp && _timestamp
         stop=`_wallclock`
diff --git a/tests/qemu-iotests/common b/tests/qemu-iotests/common
index 1e556bbb7d..1030aaf25b 100644
--- a/tests/qemu-iotests/common
+++ b/tests/qemu-iotests/common
@@ -32,6 +32,7 @@ check=${check-true}
 
 diff="diff -u"
 verbose=false
+debug=false
 group=false
 xgroup=false
 imgopts=false
@@ -132,6 +133,7 @@ s/ .*//p
 
 common options
     -v                  verbose
+    -d                  debug
 
 check options
     -raw                test raw (default)
@@ -322,6 +324,10 @@ testlist options
             verbose=true
             xpand=false
             ;;
+        -d)
+            debug=true
+            xpand=false
+            ;;
         -x)        # -x group ... exclude from group file
             xgroup=true
             xpand=false
diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index e93e62387b..04a294d747 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -338,6 +338,8 @@ def notrun(reason):
 def main(supported_fmts=[], supported_oses=['linux']):
     '''Run tests'''
 
+    debug = '-d' in sys.argv
+    verbosity = 1
     if supported_fmts and (imgfmt not in supported_fmts):
         notrun('not suitable for this image format: %s' % imgfmt)
 
@@ -347,14 +349,20 @@ def main(supported_fmts=[], supported_oses=['linux']):
     # We need to filter out the time taken from the output so that qemu-iotest
     # can reliably diff the results against master output.
     import StringIO
-    output = StringIO.StringIO()
+    if debug:
+        output = sys.stdout
+        verbosity = 2
+        sys.argv.remove('-d')
+    else:
+        output = StringIO.StringIO()
 
     class MyTestRunner(unittest.TextTestRunner):
-        def __init__(self, stream=output, descriptions=True, verbosity=1):
+        def __init__(self, stream=output, descriptions=True, verbosity=verbosity):
             unittest.TextTestRunner.__init__(self, stream, descriptions, verbosity)
 
     # unittest.main() will use sys.exit() so expect a SystemExit exception
     try:
         unittest.main(testRunner=MyTestRunner)
     finally:
-        sys.stderr.write(re.sub(r'Ran (\d+) tests? in [\d.]+s', r'Ran \1 tests', output.getvalue()))
+        if not debug:
+            sys.stderr.write(re.sub(r'Ran (\d+) tests? in [\d.]+s', r'Ran \1 tests', output.getvalue()))