A man is fighting for life after he was allegedly stabbed at a nightclub in Melbourne on Sunday morning.

Police said the 31-year-old was attacked by two unknown offenders at the venue on Chapel Street, Prahran, about 4am.

A Endeavour Hills man sustained life-threatening injuries and was taken to hospital for treatment.

The pair of offenders fled the area before police arrived, last seen heading along Macquarie Street.

Stonnington Crime Investigation Unit detectives are investigating the circumstances surrounding the incident.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au