diff --git a/src/vscp/common/mdf.cpp b/src/vscp/common/mdf.cpp
index 3e7e0c8da..29b79ccb1 100644
--- a/src/vscp/common/mdf.cpp
+++ b/src/vscp/common/mdf.cpp
@@ -704,7 +704,7 @@ CMDF_Action::clearStorage(void)
 }
 
 ///////////////////////////////////////////////////////////////////////////////
-//  getAction
+//  getActionParam
 //
 
 CMDF_ActionParameter *
@@ -721,6 +721,27 @@ CMDF_Action::getActionParam(uint16_t offset)
   return nullptr;
 }
 
+///////////////////////////////////////////////////////////////////////////////
+//  addActionParam
+//
+
+bool
+CMDF_Action::addActionParam(CMDF_ActionParameter *pactionparam)
+{
+  // Check pointer
+  if (nullptr == pactionparam) {
+    return false;
+  }
+
+  // Offset must be unique
+  if (nullptr != getActionParam(pactionparam->getOffset())) {
+    return false;
+  }
+
+  m_list_ActionParameter.push_back(pactionparam);
+  return true;
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 //  Constructor/Destructor
 //
diff --git a/src/vscp/common/mdf.h b/src/vscp/common/mdf.h
index 49f5c6d94..7027c68a4 100644
--- a/src/vscp/common/mdf.h
+++ b/src/vscp/common/mdf.h
@@ -124,6 +124,7 @@ typedef enum mdf_record_type {
   mdf_type_action_sub_item,
   mdf_type_action_param,
   mdf_type_action_param_item,
+  mdf_type_action_param_sub_item,
   mdf_type_event,
   mdf_type_event_item,
   mdf_type_event_data,
@@ -1271,6 +1272,14 @@ class CMDF_Action : public CMDF_Object {
   */
   CMDF_ActionParameter *getActionParam(uint16_t offset);
 
+  /*!
+    Add action parameter
+    @param pactionparam Pointer to action parameter to add. The offset
+    of the action parameter must be unique.
+    @return true on success, false otherwise.
+  */
+  bool addActionParam(CMDF_ActionParameter *pactionparam);
+
   /*!
     Get action parameter list
     @return Action parameter list
@@ -1392,7 +1401,7 @@ class CMDF_DecisionMatrix : public CMDF_Object {
   std::deque<CMDF_Action *> *getActionList(void) { return &m_list_action; };
 
   /*!
-    Get pointer to action object from its code
+    Get pointer to action object from 6its code
     @param code Code for action to fetch
     @return Pointer to action or nullptr if no action with that code is found.
   */