Simon Wong, 75, was last seen at a property on Sorrel Place at Catalina, in the Batemans Bay region, on Thursday, March 21.

When he could not be located or contacted, police were notified and commenced inquiries into his whereabouts.

"Police have serious concern's for Simon's welfare as he has dementia," a NSW Police spokesperson said.

Mr Wong is of Asian appearance, about 170 centimetres tall, with black hair, brown eyes and grey facial hair.

He is believed to be driving a white Hyundai Accent with paint missing on front right corner. The vehicle has a NSW registration of SW929, and may be traveling in the Queanbeyan, Wagga Wagga and Nowra areas.

Anyone with information on Mr Wong's whereabouts is urged to contact Crime Stoppers on 1800 333 000.