A man has been found dead after an apparent attempt to scale a fence behind a popular Brisbane nightclub overnight.

His body was found in laneway off Gipps Street in Fortitude Valley about midday on Sunday, a police spokesman said.

Initial investigations suggested he had been trying to climb a fence behind Birdees nightclub when he fell.

The man, whose age is at this stage unknown, had suffered severe head injuries, the spokesman said.

The venue has been approached for comment.