diff --git a/definitions/mars/grib.elda.mpp.def b/definitions/mars/grib.elda.mpp.def
index ce5e03eaf..ae2eef11e 100644
--- a/definitions/mars/grib.elda.mpp.def
+++ b/definitions/mars/grib.elda.mpp.def
@@ -1,2 +1,5 @@
 alias mars.anoffset=offsetToEndOf4DvarWindow;
 alias mars.number=perturbationNumber;
+
+unalias mars.levtype;
+unalias mars.levelist;
diff --git a/definitions/mars/grib.enda.mpp.def b/definitions/mars/grib.enda.mpp.def
index 4af93e55d..53a837ed2 100644
--- a/definitions/mars/grib.enda.mpp.def
+++ b/definitions/mars/grib.enda.mpp.def
@@ -1 +1,4 @@
 alias mars.number=perturbationNumber;
+
+unalias mars.levtype;
+unalias mars.levelist;