diff --git a/basic/qa/basic_coverage/test_variant_arg_used_as_obj.bas b/basic/qa/basic_coverage/test_variant_arg_used_as_obj.bas
new file mode 100644
index 000000000000..41ac139f639d
--- /dev/null
+++ b/basic/qa/basic_coverage/test_variant_arg_used_as_obj.bas
@@ -0,0 +1,38 @@
+'
+' This file is part of the LibreOffice project.
+'
+' This Source Code Form is subject to the terms of the Mozilla Public
+' License, v. 2.0. If a copy of the MPL was not distributed with this
+' file, You can obtain one at http://mozilla.org/MPL/2.0/.
+'
+
+Option Explicit
+
+Function doUnitTest() As String
+    TestUtil.TestInit
+    verify_VariantArgUsedAsObj
+    doUnitTest = TestUtil.GetResult()
+End Function
+
+Sub verify_VariantArgUsedAsObj
+    On Error GoTo errorHandler
+
+    Dim aResult
+    ' Without the fix, the following line would fail, triggering errorHandler reporting
+    ' "91: Object variable not set."
+    aResult = aFuncWithVarArg(0)
+    TestUtil.AssertEqualStrict(aResult, "Integer", "aResult")
+
+    Exit Sub
+errorHandler:
+    TestUtil.ReportErrorHandler("verify_VariantArgUsedAsObj", Err, Error$, Erl)
+End Sub
+
+Function aFuncWithVarArg(arg)
+    ' The 'arg' is implicitly Variant; and its following use as object (after a check),
+    ' i.e. accessing its method using dot notation, must not change the declaration type
+    If IsObject(arg) Then
+        arg.some_func()
+    End If
+    aFuncWithVarArg = TypeName(arg)
+End Function
diff --git a/basic/source/comp/exprtree.cxx b/basic/source/comp/exprtree.cxx
index db7254033e5e..2f0316428ce6 100644
--- a/basic/source/comp/exprtree.cxx
+++ b/basic/source/comp/exprtree.cxx
@@ -333,7 +333,9 @@ std::unique_ptr<SbiExprNode> SbiExpression::Term( const KeywordSymbolInfo* pKeyw
             // from 16.12.95 (similar cases possible perhaps?!?)
             if( eType == SbxOBJECT && pDef->GetType() == SbxVARIANT )
             {
-                pDef->SetType( SbxOBJECT );
+                // Do not modify the type of procedure arguments
+                if (pDef->GetScope() != SbPARAM)
+                    pDef->SetType(SbxOBJECT);
             }
             else
             {
@@ -352,7 +354,8 @@ std::unique_ptr<SbiExprNode> SbiExpression::Term( const KeywordSymbolInfo* pKeyw
     if( bObj )
     {
         // from 8.1.95: Object may also be of the type SbxVARIANT
-        if( pDef->GetType() == SbxVARIANT )
+        // (but do not modify type of procedure arguments)
+        if (pDef->GetType() == SbxVARIANT && pDef->GetScope() != SbPARAM)
             pDef->SetType( SbxOBJECT );
         // if we scan something with point,
         // the type must be SbxOBJECT