diff --git a/src/Mod/Part/App/TopoShape.cpp b/src/Mod/Part/App/TopoShape.cpp
index c3fbe56acd..b67187db38 100644
--- a/src/Mod/Part/App/TopoShape.cpp
+++ b/src/Mod/Part/App/TopoShape.cpp
@@ -1325,6 +1325,9 @@ TopoDS_Shape TopoShape::multiFuse(const std::vector<TopoDS_Shape>& shapes, Stand
     }
 #else
     BRepAlgoAPI_Fuse mkFuse;
+# if OCC_VERSION_HEX >= 0x060900
+    mkFuse.SetRunParallel(true);
+# endif
     TopTools_ListOfShape shapeArguments,shapeTools;
     shapeArguments.Append(this->_Shape);
     for (std::vector<TopoDS_Shape>::const_iterator it = shapes.begin(); it != shapes.end(); ++it) {
@@ -1410,6 +1413,7 @@ TopoDS_Shape TopoShape::generalFuse(const std::vector<TopoDS_Shape> &sOthers, St
     throw Base::AttributeError("GFA is available only in OCC 6.9.0 and up.");
 #else
     BRepAlgoAPI_BuilderAlgo mkGFA;
+    mkGFA.SetRunParallel(true);
     TopTools_ListOfShape GFAArguments;
     GFAArguments.Append(this->_Shape);
     for (const TopoDS_Shape &it: sOthers) {