A gunman is on the run after opening fire on a father-to-be and three other men in a suspected car-jacking gone wrong in the city's north-west.

Onosai Kuka, 25, was driving his two brothers and a friend to work along the Melton Highway in Taylors Lakes about 2am on Tuesday morning when shots were fired at his car.

Onosai Kuka, 25, was driving his two brothers and friend to work along the Melton Highway in Taylors Lakes about 2am on Tuesday morning when shots were fired at his car. Credit:Seven News

It's believed the gunman was in a silver sedan with a number of people inside the vehicle.

It's understood the driver of the sedan threatened to ram Mr Kuka and followed him a short distance before producing a firearm and spraying his car with bullets.