Police say a man with his face covered by a scarf approached the woman as she sat in her car on Raleigh Street, near Pascoe Vale Road in Essendon, about 10.30pm on Saturday, April 5.

The man ordered her to get out of the silver 2005 Volkswagen Golf and pulled his shirt aside to reveal a large knife, police say.

The victim complied and the man drove off with the car, turning left onto Pascoe Vale Road.

Another man then tried to use the woman's credit card at two service stations, in Thomastown and Reservoir, a short time later.

Police have released an image of the alleged carjacker and CCTV footage of two men at a service station where the victim's credit card was used.

Anyone with information has been asked to contact Crime Stoppers on 1800 333 000 or visit crimestoppers.com.au