Toronto police are trying to identify a suspect after a man's jaw was broken in an assault on a busy stretch of King Street downtown.

The incident happened in the King Street and Bathurst Street area on July 14, at around 1:45 a.m., when the area is typically packed with bar-goers.

According to Toronto police, a man and his three colleagues were leaving an establishment in the area when they spotted a group of men involved in a verbal fight.

One of the victim's colleagues intervened and was able to help stop the fight.

A few minutes later, one of the men from the fight approached the victim and punched him in the jaw "with great force" before running away.

The victim suffered extensive injuries, including a broken jaw, police said. He had to be taken to hospital to be treated.

It's not clear why the victim was attacked, police said.

On Tuesday, police released security camera images of the suspect, described as being in his early to mid-20s, and said they are appealing for help to try and identify him.

Anyone with information is being asked to contact police.