Victoria Police are offering a $350,000 reward to help solve a case where an 18-year-old Melbourne schoolgirl was abducted off the street in South Yarra and raped more than 30 years ago.

The teen had been selling flowers on the night of Friday November 22, 1985 to restaurants and was walking along Chapel Street and sometime after 10pm when she was approached by a man who threatened her and pulled her towards a car with another man inside on Bray Street.

She was bound, gagged and blindfolded, driven to an unknown property, and seriously sexually assaulted over a number of hours while still blindfolded. She was then dumped on Yarra Boulevard in Richmond around 1am on Saturday, November 23.

Detectives believe three men were involved in the attack. The victim died in 2008.

Investigators have filmed a recreation of the victim being grabbed on the street in South Yarra. Officer in charge of the Sexual Crimes Squad, Detective Inspector Steve Wilson, said he believes the reward and re-enactment could prove crucial in solving the case.

"This horrific incident may have happened over 30 years ago, however ensuring that those responsible are brought to justice remains as important to us as ever," he said.

"I absolutely believe that with the right information, it can be solved."

He said the attack was particularly brutal and would have had a significant effect on the victim.

"Our victim was still at school at the time of the abduction and assault - she was really just a kid," he said.

"She was studying for her final year exams and ended up delaying them while she coped with the aftermath.

"I think she showed great strength of character to go on with her life the way she did, she lived overseas and was known as a very active person.

"Police are looking for anyone who might have witnessed the incident in Bray Street and can provide information about the men or the vehicle to come forward.

"We know that from the victim's statement, there was a man who made eye contact with her at the end of the street before getting to his vehicle and driving off."

© AAP 2019