A man is fighting for his life after he was hit over the head with an unknown weapon by a group of men, who police believe were strangers to him, in West Melbourne.

Key points: The man is in a critical condition in hospital after being hit in the head

The man is in a critical condition in hospital after being hit in the head Detectives don't believe the incident was a carjacking or burglary

Detectives don't believe the incident was a carjacking or burglary Police have urged any motorists with dash-cam footage of King Street at 4:30am to contact them

Police said the 27-year-old Seabrook man was taken to hospital with serious head injuries at 4:50am today.

Acting Detective Sergeant Simon Watts said the victim got out of the passenger seat of a car on the corner of King Street and Roden Street before the assault.

"We're not sure why he's gotten out of his car, he's been confronted by a group of African males, hit in the head and seriously assaulted," he said.

"There was a weapon, what that actual weapon is, we're not sure, but it was used to assault this male and he has suffered some serious head injuries as a result.

"It was quite brutal, quite confronting, it's certainly a serious crime."

Acting Detective Sergeant Watts said police did not believe the incident was a carjacking and did not believe anything was stolen in connection with the attack.

He said witnesses said there were two car loads of attackers, who were travelling in a red Subaru and a red Mitsubishi.

"So, anywhere between maybe five to 10 [men]," he said.

Detectives are on the scene, investigating the incident and have urged any witnesses or motorists with dash-cam footage of King Street from around 4:30am to contact Crime Stoppers.

No arrests have been made.