NSW Police have arrested a man in Goulburn and charged him over a number of sexual violence offences dating back more than 20 years.

Police from Campbelltown have charged the 51-year-old man over two alleged sexual assaults from 1989.

"In March 1989, a 24-year-old woman was picked up by a man driving a car and taken to a bush clearing in Wedderburn, where she was allegedly assaulted and then sexually assaulted," police said in a statement.

"In November of the same year, a 47-year-old woman was asleep in a caravan in Appin when an unknown man allegedly broke in and threatened her with a knife, before sexually assaulting her."

No arrests were made at the time, but evidence taken from the scene was submitted for DNA review recently, leading to the arrest on Tuesday.

The man was refused bail and will appear in Campbelltown Local Court on Wednesday, April 10.