A man who died after being found unconscious in a Melbourne street likely hit his head after falling in a police cell, but a coroner has been unable to determine the cause of his death.

Abdi Hasan, 29, was found unconscious outside a public housing estate in Carlton in January 2009.

He died in hospital from a head injury the next day.

Mr Hasan, a Somalian refugee, had been in a fight with a friend the previous day.

The inquest into his death heard that he had also appeared to hit his head on a concrete wall when he lost his footing in a police cell.

Delivering her finding on Tuesday, Coroner Jennifer Coate said she could not say which of the two episodes caused the head injury that led to Mr Hasan's death, or if he died as a result of another incident.

Mr Hasan, who was in the Fitzroy police cell for being drunk in a public place, was captured on CCTV footage losing his footing as he went to sit down and appeared to hit the left side of the back of his head on the concrete wall.

However, he appeared to be speaking normally when he left the police station four hours later.

About an hour-and-a-half later, Mr Hasan lay on the grass outside public housing flats in Carlton and lost consciousness.

An ambulance was called after he had been lying there for more than two hours, the inquest heard.

The previous day Mr Hasan had been involved in a fight with a friend at public housing flats in Richmond.

A security guard observed that Mr Hasan was unsteady on his feet and falling over.

His friend was carrying a dumbbell but there is no evidence to suggest he struck Mr Hasan with it.

Coroner Jennifer Coate said it was not possible to pinpoint a cause of death.

"The fatal intracranial bleed which caused Abdi's death was caused by one or more episodes of blunt force trauma to his head," she said.

"It is not possible to pinpoint the timing of that blunt force trauma or to assign any one of the observed events of minor trauma to his head in the last 24 hours of his life as the likely cause."