A 24-year-old ‘Good Samaritan’ is in hospital with stab wounds to his abdomen after trying to stop an assault on a woman in central Melbourne.

Melbourne Crime Investigation Unit detectives believe two other men were also assaulted before the stabbing in Southbank on Friday.

The ‘heroic’ victim had just finished work at a nearby restaurant when he was stabbed while trying to help a woman who was being attacked.

As the victim interrupted the assault, the offender turned on him and stabbed him in the left side of his abdomen.

He was taken to hospital with non-life threatening injuries.

Detectives said the attacker fled down the Yarra Promenade shortly before midnight and his female victim also fled the scene.

Investigators are urging the woman who was assaulted to come forward to police.

Police also believe that before the stabbing, the offender was approaching people walking along the promenade, trying to start a fight.

They want to talk to two other men they believe were assaulted before to the stabbing.

The offender is described as being approximately 180cm tall and wearing a black and white cap, white t-shirt and white runners.

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