Sophie Worsnop-Hair says she was targeted three times in the space of 100 metres by fake rideshare drivers in Melbourne one night.

Key points: Several women claim imposter rideshare drivers have harassed them

Several women claim imposter rideshare drivers have harassed them Police continue to investigate a sexual assault case involving an alleged fake rideshare driver in Prahran

Police continue to investigate a sexual assault case involving an alleged fake rideshare driver in Prahran Uber and police urge riders to verify driver details before getting in a car

After grabbing a bite to eat on Sunday night, the bar manager said she was walking alone back to work in Little Bourke Street in Melbourne's CBD when men in three separate cars pulled up to her, claiming to be her Uber driver.

The only problem was Ms Worsnop-Hair never ordered one.

The 24-year-old said she avoided the first by pretending to be on the phone.

She became more concerned when a second driver stopped and insisted she get inside.

"He was getting aggressive and I had to walk away from him as well, he followed me for a bit and then left," Ms Worsnop-Hair said.

She continued walking, but then a third car stopped. This time, the driver would not take no for an answer.

"He became pretty violent towards me, yelling at me," she said.

"He said 'Get in the car' over and over, and it wasn't until I had to threaten him with reporting him to the police that he left me alone."

Ms Worsnop-Hair said the street was quiet at the time, and believed it was not a misunderstanding or possible mistaken identity.

Others targeted by 'imposter' drivers

Police urge passengers to report rideshare frauds to authorities. ( ABC News: Mitch Woolnough )

It comes after a 27-year-old woman was sexually assaulted by a man pretending to be an Uber driver on Chapel Street in Prahran, after she got into his car early on September 1.

Victoria Police said investigations were ongoing.

Last week, a man using the registration of another Uber driver was jailed for at least three years and four months after pleading guilty to raping a passenger he picked up in Richmond last year.

Ms Worsnop-Hair made a police report and shared her story on social media on Sunday night.

She remained shaken by the incident, and has been inundated by messages from others around Melbourne who claim to have had similar experiences with imposter rideshare drivers.

The ABC has spoken to more than five other people, who claim they were approached by fake rideshare drivers.

One claimed she was accosted outside a Brunswick supermarket in the middle of the day.

Twenty-five-year-old Matt, who did not want his last name published, said he mistakenly got into a car last year, thinking it was the Uber he ordered.

Matt said he was intoxicated and the driver stole his phone when he fell asleep.

"I called Uber they said there was no history of the ride. He wasn't my driver at all," he said.

'Black market' of rideshare accounts growing

Several women contacted Ms Worsnop-Hair after she shared her story on social media. ( ABC Melbourne: Kristian Silva )

The secretary of the Ride Share Drivers' Association of Australia, Les Johnson, said it was hard to judge how big the problem of unauthorised drivers was.

"I can assure you it's something that's happening across the board," he said.

"They have no accreditation, they have no insurance. It really is a nightmare."

Mr Johnson said a "black market" among Uber drivers was developing, where some were selling their accounts to people who bypassed photo verification checks in the app by holding up a piece of paper with a photo.

In a statement, Victoria Police said they were working closely with rideshare services and were looking at ways to combat the emerging crime.

"We encourage people to ensure they check the vehicle and driver before getting in the vehicle, and if they have any concerns or suspicions to decline the ride," a police spokeswoman said.

She urged any passengers concerned about fraudulent activity to contact the rideshare company and to make a police report.

Uber urges riders to check app details

An Uber spokeswoman said the company had introduced several safety measures, including GPS tracking, detailed ride information for passengers, and background checks for drivers.

"These advances in safety are important — but for them to be effective you need to be in the right car," she said.

"You should never get in a car with a driver who claims to be with Uber but doesn't match what is in your app."

RMIT University criminologist Marietta Martinovic said the incidents served as a "wake-up call" for ridesharing services.

"Although it is a really small percentage of these rides that go horribly wrong, imposters go around nightspots where people are vulnerable," Dr Martinovic said.

Dr Martinovic acknowledged that the ridesharing services were not at fault for fake drivers, but called on them to improve safety measures to reduce further incidents.