One man is in a critical condition and another has leg injuries after two separate hit and runs in Melbourne.

A cyclist was knocked from his bike by a red Commodore on the corner of Stud Road and Evans Street in Scoresby around 6:00pm (AEST).

The driver did not stop despite dragging the bike almost 20 metres.

Meanwhile, a 28-year-old man is fighting for his life in hospital after being hit by a car on Ballarat Road in Footscray at 8:30pm.

Police believe they have found the car dumped in a laneway in nearby Maribyrnong.

But Detective Acting Senior Sergeant Mike Amos says they are still searching for the driver who fled without helping the victim.

"We can always sit and describe them as being callous and those sorts of things, but over many years I've learnt there's always an explanation for it," he said.

"At this point in time that's exactly what we want to hear, is just why he didn't (stop).

"Come explain it and we'll deal with what is a bad situation, start to make it as good as we possibly can."

And a Yarra Junction man has been killed after being struck by a car in Seville, east of Melbourne.

The 55-year-old man was hit while walking along the Monbulk-Seville Road around 7:00pm.