New South Wales Police have called for community assistance to help find Ivan, a 75-year-old man from Leppington with dementia.

He has been missing since the weekend and is wearing a white Adidas t-shirt, dark navy shorts, white socks, and dark-coloured shoes, and also goes by the name John.

He is believed to be travelling on foot, but police say he is extremely mobile and could be in other suburbs.

Anyone who sees him is urged to contact Crimestoppers on 1800 333 000 or Liverpool City Police Area Command.