diff --git a/modules/objc/generator/gen_objc.py b/modules/objc/generator/gen_objc.py
index bd9743c757..61d5e140ab 100755
--- a/modules/objc/generator/gen_objc.py
+++ b/modules/objc/generator/gen_objc.py
@@ -570,7 +570,7 @@ def get_swift_type(ctype):
     return swift_type
 
 def build_swift_extension_decl(name, args, constructor, static, ret_type):
-    extension_decl = ("class " if static else "") + (("func " + name) if not constructor else "convenience init") + "("
+    extension_decl = "@nonobjc " + ("class " if static else "") + (("func " + name) if not constructor else "convenience init") + "("
     swift_args = []
     for a in args:
         if a.ctype not in type_dict: