diff --git a/opm/parser/eclipse/EclipseState/Grid/MULTREGTScanner.hpp b/opm/parser/eclipse/EclipseState/Grid/MULTREGTScanner.hpp
index aaff80f73..c7d5b03b7 100644
--- a/opm/parser/eclipse/EclipseState/Grid/MULTREGTScanner.hpp
+++ b/opm/parser/eclipse/EclipseState/Grid/MULTREGTScanner.hpp
@@ -73,7 +73,7 @@ namespace Opm {
 
     private:
         void addKeyword( const Eclipse3DProperties& props, const DeckKeyword& deckKeyword, const std::string& defaultRegion);
-        void assertKeywordSupported(const DeckKeyword& deckKeyword, const std::string& defaultRegion);
+        void assertKeywordSupported(const DeckKeyword& deckKeyword);
         std::vector< MULTREGTRecord > m_records;
         std::map<std::string , MULTREGTSearchMap> m_searchMap;
         const Eclipse3DProperties& m_e3DProps;
diff --git a/src/opm/parser/eclipse/EclipseState/Grid/MULTREGTScanner.cpp b/src/opm/parser/eclipse/EclipseState/Grid/MULTREGTScanner.cpp
index f5b0e5933..c0389ad0f 100644
--- a/src/opm/parser/eclipse/EclipseState/Grid/MULTREGTScanner.cpp
+++ b/src/opm/parser/eclipse/EclipseState/Grid/MULTREGTScanner.cpp
@@ -138,7 +138,7 @@ namespace Opm {
     }
 
 
-    void MULTREGTScanner::assertKeywordSupported( const DeckKeyword& deckKeyword, const std::string& /* defaultRegion */) {
+    void MULTREGTScanner::assertKeywordSupported( const DeckKeyword& deckKeyword) {
         for (const auto& deckRecord : deckKeyword) {
             const auto& srcItem = deckRecord.getItem("SRC_REGION");
             const auto& targetItem = deckRecord.getItem("TARGET_REGION");
@@ -157,8 +157,7 @@ namespace Opm {
 
 
     void MULTREGTScanner::addKeyword( const Eclipse3DProperties& props, const DeckKeyword& deckKeyword , const std::string& defaultRegion) {
-        assertKeywordSupported( deckKeyword , defaultRegion );
-
+        assertKeywordSupported( deckKeyword );
         for (const auto& deckRecord : deckKeyword) {
             std::vector<int> src_regions;
             std::vector<int> target_regions;