diff --git a/tests/grib_mars_keys2.sh b/tests/grib_mars_keys2.sh
index 2396e0236..224279019 100755
--- a/tests/grib_mars_keys2.sh
+++ b/tests/grib_mars_keys2.sh
@@ -11,7 +11,9 @@
 . ./include.ctest.sh
 
 label="grib_mars_keys2_test"
+tempOut=temp.${label}.out
 tempGrib=temp.${label}.grib
+tempRef=temp.${label}.ref
 
 grib1_sample=$ECCODES_SAMPLES_PATH/GRIB1.tmpl
 grib2_sample=$ECCODES_SAMPLES_PATH/reduced_gg_pl_32_grib2.tmpl
@@ -27,6 +29,82 @@ grib_check_key_equals $tempGrib mars.class,mars.type,mars.stream 'yt em dcwv'
 grib_check_key_equals $tempGrib marsClass:i,marsType:i,marsStream:i '18 17 1029'
 
 
+# Check unalias
+# -----------------
+${tools_dir}/grib_set -s stream=gfas,type=ga $grib2_sample $tempGrib
+${tools_dir}/grib_ls -jm $tempGrib > $tempOut
+cat > $tempRef << EOF
+{ "messages" : [ 
+  {
+    "domain": "g",
+    "date": 20100912,
+    "time": 1200,
+    "expver": "0001",
+    "class": "od",
+    "type": "ga",
+    "stream": "gfas",
+    "step": 0,
+    "levelist": 1000,
+    "levtype": "pl",
+    "param": 130
+  }
+]}
+EOF
+diff $tempRef $tempOut
+
+# This combo unaliases mars.levelist and mars.step
+${tools_dir}/grib_set -s stream=gfas,type=gsd $grib2_sample $tempGrib
+${tools_dir}/grib_ls -jm $tempGrib > $tempOut
+cat > $tempRef << EOF
+{ "messages" : [ 
+  {
+    "domain": "g",
+    "date": 20100912,
+    "time": 1200,
+    "expver": "0001",
+    "class": "od",
+    "type": "gsd",
+    "stream": "gfas",
+    "param": 130
+  }
+]}
+EOF
+diff $tempRef $tempOut
+${tools_dir}/grib_dump -Da $grib2_sample > $tempOut
+grep -q "g2level level = 1000 .vertical.level, mars.levelist" $tempOut
+${tools_dir}/grib_dump -Da $tempGrib > $tempOut
+set +e
+grep -w levelist $tempOut # dump should not show levelist
+status=$?
+set -e
+[ $status -ne 0 ]
+
+
+# GRIB1
+# This combo unaliases mars.step
+${tools_dir}/grib_set -s localDefinitionNumber=31,stream=esmm,type=em $grib1_sample $tempGrib
+${tools_dir}/grib_ls -jm $tempGrib > $tempOut
+cat > $tempRef << EOF
+{ "messages" : [ 
+  {
+    "domain": "g",
+    "levtype": "pl",
+    "levelist": 500,
+    "time": 1200,
+    "param": 129.128,
+    "class": "od",
+    "type": "em",
+    "stream": "esmm",
+    "expver": "0001",
+    "fcmonth": 0,
+    "date": 0
+  }
+]}
+EOF
+diff $tempRef $tempOut
+
+
+
 # Check all combinations
 # ------------------------
 i=0
@@ -43,5 +121,6 @@ for cfg in $ECCODES_DEFINITION_PATH/mars/grib.*.*.def; do
 done
 echo "Checked $i files"
 
+
 # Clean up
-rm -f $tempGrib
+rm -f $tempGrib $tempRef $tempOut