diff --git a/bin/tools/RunFunctions b/bin/tools/RunFunctions
index e350b44ad..50ddc1ed3 100644
--- a/bin/tools/RunFunctions
+++ b/bin/tools/RunFunctions
@@ -75,7 +75,14 @@ runParallel ()
         echo "$APP_NAME already run on $PWD: remove log file to run"
     else
         echo "Running $APP_NAME in parallel on $PWD using $1 processes"
-        ( mpirun -np $1 $APP_RUN -parallel < /dev/null > $LOG_NAME 2>&1 )
+	if [ -z "$WM_MPIRUN_PROG" ]
+	then
+	    mpirunProg=mpirun
+	else
+	    # Allow exceentric systems to override the hardcoded mpirun
+	    mpirunProg=$WM_MPIRUN_PROG
+	fi
+        ( $mpirunProg -np $1 $APP_RUN -parallel < /dev/null > $LOG_NAME 2>&1 )
     fi
 }
 
diff --git a/etc/settings.sh b/etc/settings.sh
index 2e28f05fd..13c4de270 100755
--- a/etc/settings.sh
+++ b/etc/settings.sh
@@ -248,7 +248,13 @@ MACPORTOPENMPI)
 	export FOAM_MPI_LIBBIN=$FOAM_LIBBIN/$FOAM_MPI
 	_foamAddLib     $libDir
 	unset libDir
-	;;
+
+	which mpirun >/dev/null
+	if [ $? -ne 0 ]
+	then
+	    export WM_MPIRUN_PROG=mpirun-openmpi-$WM_MACPORT_MPI_VERSION
+	fi
+ 	;;
 
 MACPORTMPICH)
     export FOAM_MPI=mpich-macports-$WM_MACPORT_MPI_VERSION
@@ -260,6 +266,11 @@ MACPORTMPICH)
     _foamAddLib     $libDir
     unset libDir
 
+    which mpirun >/dev/null
+    if [ $? -ne 0 ]
+    then
+	export WM_MPIRUN_PROG=mpirun-mpich-$WM_MACPORT_MPI_VERSION
+    fi
     ;;
 
 SYSTEMOPENMPI)