Police are searching for two men who escaped from the Maribyrnong Detention Centre just after 1am on Wednesday.
Leonard Gjeka, a South Australian bikie gang associate, escaped with fellow detainee, Michael Dobson.
Police believe the two left the main building of the facility on Hampstead Road and were met by two people. All four left through a gate on the south side of the centre.
Local police and the dog squad searched the area but were unable to locate the escapees.
Detectives from the Fugitive Taskforce are investigating the incident.
Dobson, 51, is a New Zealand national described as having a fair complexion, medium build and blonde hair.
Gjeka, 32, is an Albanian national and has a solid build, 180cm tall, has brown eyes, black hair and an olive complexion.
Investigators have released images of the escapees.
Anyone who sees either of the men is being urged to contact triple-0 immediately.
