diff --git a/bin/mpirunDebug b/bin/mpirunDebug
index 1e901b25aa..695c0fae5e 100755
--- a/bin/mpirunDebug
+++ b/bin/mpirunDebug
@@ -7,7 +7,7 @@
 #    \\/     M anipulation  |
 #------------------------------------------------------------------------------
 #     Copyright (C) 2011-2015 OpenFOAM Foundation
-#     Copyright (C) 2017-2021 OpenCFD Ltd.
+#     Copyright (C) 2017-2023 OpenCFD Ltd.
 #------------------------------------------------------------------------------
 # License
 #     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
@@ -45,6 +45,7 @@ options:
   -local        Same as -spawn=1
   -remote       Same as -spawn=2
   -clean        Remove old processor*.{log,sh} files, mpirun.schema etc
+  -decompose-dict=<file>   Specific decomposeParDict name
   -help         Print the usage
 
 Invoke mpirun with separate per-processor log files or running in
@@ -111,7 +112,7 @@ Linux)
 esac
 
 unset appName appArgs nProcs
-unset method spawn optClean
+unset method spawn optClean optValue
 optConfirm=true
 
 decompDict="system/decomposeParDict"
@@ -126,7 +127,7 @@ do
     then
         knownOption=true  # Assume success
         case "$1" in
-        '') ;;  # ignore junk
+        ('') ;;  # Ignore junk
 
         -clean)     optClean=true ;;
         -yes)       unset optConfirm ;;
@@ -173,14 +174,25 @@ do
             shift
             ;;
 
+        (-decompose-dict=*)
+            optValue="${1#*=}"
+            case "$optValue" in
+            ('' | none | false) ;;  ## Ignore
+            (*)
+                decompDict="$optValue"
+                appArgs="${appArgs}${appArgs:+ }-decomposeParDict '$decompDict'"
+                ;;
+            esac
+            ;;
+
         -decomposeParDict)
             # Grab values and add to args immediately
             decompDict="$2"
-            appArgs="${appArgs}${appArgs:+ }$1 '$2'"
             shift
+            appArgs="${appArgs}${appArgs:+ }-decomposeParDict '$decompDict'"
             ;;
 
-        *)
+        (*)
             knownOption=false  # Fallthrough to regular processing
             ;;
         esac
@@ -192,23 +204,24 @@ do
         fi
     fi
 
+    # Processing application arguments
     case "$1" in
-    -help* | --help*) usage ;;
-    '') ;;  # ignore junk
+    (-help* | --help*) usage ;;
+    ('') ;;  ## Ignore junk
 
-    -np)
+    (-np)
         nProcs="$2"
         shift
         ;;
 
-    -decomposeParDict)
+    (-decomposeParDict)
         # Grab values and add to args immediately
         decompDict="$2"
-        appArgs="${appArgs}${appArgs:+ }$1 '$2'"
+        appArgs="${appArgs}${appArgs:+ }-decomposeParDict '$decompDict'"
         shift
         ;;
 
-    *)
+    (*)
         if [ -z "$appName" ]
         then
             appName="$1"
diff --git a/bin/tools/RunFunctions b/bin/tools/RunFunctions
index 5ef1c3c23a..f8482f63f2 100644
--- a/bin/tools/RunFunctions
+++ b/bin/tools/RunFunctions
@@ -6,7 +6,7 @@
 #    \\/     M anipulation  |
 #------------------------------------------------------------------------------
 #     Copyright (C) 2011-2016 OpenFOAM Foundation
-#     Copyright (C) 2015-2022 OpenCFD Ltd.
+#     Copyright (C) 2015-2023 OpenCFD Ltd.
 #------------------------------------------------------------------------------
 # License
 #     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
@@ -180,6 +180,16 @@ getNumberOfProcessors()
 {
     local dict="${1:-system/decomposeParDict}"
 
+    case "$dict" in
+    (system/*)  # Already qualified
+        ;;
+    (*)
+        # If it does not exist, assume it refers to location in system/
+        [ -f "$dict" ] || dict="system/$dict"
+        ;;
+    esac
+
+
     # Re-use positional parameters for automatic whitespace elimination
     set -- $(foamDictionary -entry numberOfSubdomains -value "$dict" 2>/dev/null)
 
@@ -223,7 +233,7 @@ getApplication()
 #
 runApplication()
 {
-    local appName appRun logFile logMode
+    local appName appRun optValue logFile logMode
 
     # Any additional parsed arguments (eg, decomposeParDict)
     local appArgs
@@ -232,25 +242,39 @@ runApplication()
     while [ "$#" -gt 0 ] && [ -z "$appRun" ]
     do
         case "$1" in
-            -a | -append)
-                logMode=append
-                ;;
-            -o | -overwrite)
-                logMode=overwrite
-                ;;
-            -s | -suffix)
-                logFile=".$2"
-                shift
-                ;;
-            -decomposeParDict)
-                appArgs="$appArgs $1 $2"
-                shift
-                ;;
-            '')
-                ;;
-            *)
-                appRun="$1"
-                ;;
+        ('') ;;  # Ignore junk
+
+        (-a | -append)
+            logMode=append
+            ;;
+        (-o | -overwrite)
+            logMode=overwrite
+            ;;
+        (-s | -suffix)
+            logFile=".$2"
+            shift
+            ;;
+
+        (-decompose-dict=*)
+            optValue="${1#*=}"
+            case "$optValue" in
+            ('' | none | false) ;;  ## Ignore
+            (*) appArgs="$appArgs -decomposeParDict $optValue" ;;
+            esac
+            ;;
+
+        (-decomposeParDict)
+            optValue="$2"
+            shift
+            case "$optValue" in
+            ('' | none | false) ;; ## Ignore
+            (*) appArgs="$appArgs -decomposeParDict $optValue" ;;
+            esac
+            ;;
+
+        (*)
+            appRun="$1"
+            ;;
         esac
         shift
     done
@@ -280,7 +304,7 @@ runApplication()
 #
 runParallel()
 {
-    local appName appRun logFile logMode nProcs
+    local appName appRun optValue logFile logMode nProcs
 
     # Any additional parsed arguments (eg, decomposeParDict)
     local appArgs="-parallel"
@@ -295,30 +319,46 @@ runParallel()
     while [ "$#" -gt 0 ] && [ -z "$appRun" ]
     do
         case "$1" in
-            -a | -append)
-                logMode=append
+        ('') ;;  # Ignore junk
+
+        (-a | -append)
+            logMode=append
+            ;;
+        (-o | -overwrite)
+            logMode=overwrite
+            ;;
+        (-s | -suffix)
+            logFile=".$2"
+            shift
+            ;;
+        (-n | -np)
+            nProcs="$2"
+            shift
+            ;;
+        (-decompose-dict=*)
+            optValue="${1#*=}"
+            case "$optValue" in
+            ('' | none | false) ;;  ## Ignore
+            (*)
+                appArgs="$appArgs -decomposeParDict $optValue"
+                nProcs="$(getNumberOfProcessors "$optValue")"
                 ;;
-            -o | -overwrite)
-                logMode=overwrite
-                ;;
-            -s | -suffix)
-                logFile=".$2"
-                shift
-                ;;
-            -n | -np)
-                nProcs="$2"
-                shift
-                ;;
-            -decomposeParDict)
-                appArgs="$appArgs $1 $2"
-                nProcs=$(getNumberOfProcessors "$2")
-                shift
-                ;;
-            '')
-                ;;
-            *)
-                appRun="$1"
+            esac
+            ;;
+        (-decomposeParDict)
+            optValue="$2"
+            shift
+            case "$optValue" in
+            ('' | none | false) ;;  ## Ignore
+            (*)
+                appArgs="$appArgs -decomposeParDict $optValue"
+                nProcs="$(getNumberOfProcessors "$optValue")"
                 ;;
+            esac
+            ;;
+         (*)
+            appRun="$1"
+            ;;
         esac
         shift
     done