A teenager has been punched in the head, knocked out and raped by an unknown man on a street in regional NSW.

NSW Police are hunting the man after the 19-year-old was grabbed as she walked through Goulburn in the Southern Tablelands, on Friday night.

She was thrown to the ground, punched several times in the face, lost consciousness before being sexually assaulted.

When the woman regained consciousness, she ran to a nearby home and flagged down a passing driver who took her to a police station.

Detective Superintendent Jayne Doherty says officers from the State Crime Command’s Sex Crimes Squad have established Strike Force Noobillia to investigate.

“Someone in Goulburn knows who this male is,” Det Supt Doherty told reporters on Wednesday.

“We don’t want people to be alarmed but they should be alert.”

Police believe the incident on Bourke Street may be linked to an assault on nearby Blackshaw Road the previous week.

On April 5, an 18-year-old woman was also punched in the face by an unknown man but escaped.

The man is described as in his late 30s to early 40s, about 180cm tall, with a solid build and scruffy beard.