Man bound during NSW robbery

A man has been tied up and threatened with a knife by two men claiming to be police officers in NSW's Illawarra region.

The pair forced the 53-year-old to the ground after knocking at the door of his campervan in Barrack Heights on Wednesday afternoon, police said.

The men put tape over the man's eyes and around his legs and hands, before demanding money.

They fled when they were disturbed by one of the 53-year-old's relatives, who had dropped by.

He is being treated for cuts to his hands, head and arms and his alleged attackers remain at large.