Appeal for info on Melbourne sex attack

Detectives have launched a fresh appeal for information over the sexual assault of a woman in inner Melbourne last year.

The 31-year-old woman was running along the foreshore on Beaconsfield Parade in Middle Park between 11pm and 11.30pm on February 5 when she was grabbed from behind.

She was forced face down into the sand and sexually assaulted before a man and a woman came to her aid along with two other men wearing white shirts. The offender then fled.

At the time, CCTV was released of a man wanted in relation to the attack and the image has been released again.

Police also are still keen to speak to the woman who helped the victim as well as one of the men wearing a white shirt who are yet to come forward.

Detective Senior Constable Boris Di Camillo said any piece of information, no matter how small, could prove crucial.

"We're keen to speak to anyone who recognises this man in any way - it could be someone they know or even just someone they have seen in their local area," he said in a statement on Thursday.

"This was an incredibly traumatic incident for the victim to go through and as you can imagine has had a significant impact on her wellbeing."