A man in his 30s has died after being found with his throat cut in a Melbourne hotel in the early hours of Sunday morning.

Paramedics were called to Crown Metropol on Whiteman Street, Southbank, just after 2:30am on Sunday but the man died at the scene.

Police said the circumstances surrounding the man's death have yet to be established but it was being treated as suspicious.

Guests saying at the hotel said half of the eighth floor was in lockdown and forensic police were examining the scene.

Extra security personnel are now guarding the hotel's lifts.

Detective Sergeant Nathan Favre said it did not appear to be a result of a domestic dispute and they were still hunting for the suspect.

"The reason for the altercation is not clear at this stage, we don't believe it's domestic related," he said.

"There's no indication of this relating to gangs or drugs ... there's no indication of organised crime.

"We believe the parties [were] known to each other and [the attack was] not random.

"The actual assault we believe was confined to the hotel room."

Detective Sergeant Favre said one witness who had been in the hotel room had made a statement to police.

"There was a person who made themselves known to staff that has assisted us, who has observed the male injured within the room and that's prompted them to call authorities," he said.

"It's not clear who was a guest in the room at the time.

"There's an element of violence which is distressing. Without going into the injuries, we certainly believe there's been a violent event that's lead to the death. It's troubling."