A group of carjackers remains on the run two months after assaulting a man who tried to thwart the theft when he heard his car alarm go off in Melbourne's west.

The 36-year-old Braybrook man said went to investigate when he heard the alarm of his Toyota Camry sound about 4.10pm on May 26.

He spotted a group of men trying to steal his black sedan – which was parked on Churchill Avenue, Braybrook – and he was assaulted when he tried to intervene.

Police have released images of men they would like to speak to over the carjacking in Braybrook in May. Credit:Victoria Police

Police say the group pried his car keys from him while he was unconscious and fled in his car before crashing it into a fence and abandoning it shortly after.