A dash cam video has captured the dramatic moment a car knocked two motorcyclists from their bikes in Melbourne.

The crash happened just after 1:30pm on Sunday on Raleigh Road, Maribyrnong, in the city's north-west.

The footage shows one of the motorcyclists being thrown into the air as the car turns into oncoming traffic.

An Ambulance Victoria spokeswoman said the two men, a 42-year-old and a 37-year-old, were taken to hospital in a stable condition.

The woman driving the car, a 23-year-old from Sunshine West, was also taken to hospital for observation.

One of the riders, speaking from hospital, said neither he or his friend on the other bike had time to react.

"Not even touch the brakes, nothing," he said.

"I do remember hitting the car and flying in the air, and the ground, and it sort of went black after that.

"I just count my lucky stars that me and my mate have come out of it. We are banged up but it could have been a lot worse."

Kate Mackintosh, who witnessed the crash, said the riders were lucky to be alive.

"The first thing I saw was one of the men flying in the air and landing in the gutter," she said.

"It didn't seem quite real when it was happening ... it was like the whole world kind of just stopped and we just watched him and we saw him land.

"There were no brakes, no nothing, just bang - that was it."

Police said they were investigating the incident and charges had not been laid at this stage.