A man passed out during a garotte-style attack by two robbers, NSW police say.

The 42-year-old was with his dogs on a beach at Bulli on the state's south coast on Monday when he stopped and sat down on a rock at about 8.45pm.

Police say two men approached and asked for a cigarette.

As the dog-walker handed one over, one of the men placed a white cord around his neck while demanding his phone and wallet.

He pulled the cord so tight the victim lost consciousness, and when he came to he found money missing from his wallet.

The victim was taken to Wollongong Hospital where he was treated for minor injuries and shock.

Investigators say they are looking for two men of Pacific Islander appearance.

One was described as being aged about 17-18 years, with a stocky build and wearing a blue T-shirt with dark writing and a tan coloured beanie cap.

He was wearing tracksuit pants that were rolled up at the bottom.

The second man was taller and wearing a dark-coloured hoodie.

AAP