Photo: nottstv.com

Investigators have been told a North Melbourne man and a North Melbourne woman, both aged in their 40s, were on a tram headed along Flemington Road from the city about 7.15pm on Saturday.

As the tram reached the Royal Melbourne Hospital a fellow passenger carrying a beer bottle approached the couple.

He made disparaging remarks about the woman before grabbing the man around the neck and attempting to assault him.

During the struggle a picture belonging to one of the victims was broken.

The offender got off the tram a short time later and was last seen walking east along Grattan Street.

He is perceived to be Caucasian, clean shaven and was wearing dark track pants and a dark top.

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