2004 Nissan Micra central locking noise?

When I use the remote to lock the car there is a loud rasping noise coming from the drivers door. The noise is coming from the location beside where the drivers right shoulder would be. The locking system works ok but the noise last for about 1 second. It does not happen when unlocking. If I use the internal syatem when in the car there is no noise and the doors lock ok. Worried that I could be locked out at some stage.