Police have released security footage of a shocking punch-up that resulted in two young men from Reservoir being bashed unconscious in a Brunswick laneway after defending their girlfriends.

Two women were dancing at the Penny Black on Sydney Road when they were approached by an unknown man who allegedly tried to make the women kiss by forcing their heads together.

The two women's boyfriends, aged 21 and 23, stepped in and argued with the man who was later removed by a bouncer.

The offenders and victims first clashed at the Penny Black in Brunswick. (Supplied)

When the two women and their boyfriends left the venue at about 1.20am, they were confronted by a group of men including the man who had been kicked out of the bar.

CCTV video shows the two male victims being assaulted by the group of men, both kicked in the head after being knocked to the ground unconscious.

The men were taken to hospital with facial fractures, broken teeth and concussion.

The men were kicked in the head after being knocked to the ground. (Supplied)

The two victims suffered broken teeth, facial fractures and concussions. (Supplied)

Detective senior constable Bryan Strangman said the two men were quite traumatised by the assault.

"It's very unexpected, very cowardly," he said.

The offenders are described as being of Middle Eastern appearance.