A 40-year-old man burnt to death inside his shack in Cullinan, east of Tshwane, said police on Sunday.

Police spokesman Johannes Jaftha said the incident occurred in Refilwe Extension Five at 11pm on Saturday night.

He said the man ? who was staying alone ? was asleep when his shack mysteriously went up in flames.

"One of his neighbours saw the flames and called the fire brigades and the cops.

"The fire fighters responded quickly and managed to put out the fire even before it raged to other shacks.

"But it was too late as the victim had already burnt to death," he said.

The identity of the deceased was not released.

The cop said the cause of the fire was not known and it was being investigated.

He said they cannot rule out the possibility that it was started by lightning as the weather was stormy in that area at the time.

An inquest docket has also been opened for investigation.