The South Australian government must investigate an Adelaide prison escape to ensure it doesn't happen again, the state opposition says.
Jake Devenney-Gill was seen running north from the pre-release, low-security section of Yatala Prison on Sunday night.
No details of his offending have been released but he is not considered dangerous and is not thought to be armed.
He is described as about 170cm tall with a slim build and blond hair in a rat or pony tail, wearing black shorts and a blue T-shirt or singlet.
Opposition correctional services spokesman John Gardner says it is always concerning when a prisoner escapes and potentially puts the community at risk.
"South Australians deserve a full investigation and explanation as to why this has happened, and an assurance that the government is actively taking steps to ensure it doesn't happen again," he said on Monday.
Mr Gardner said the escape came as SA's prisons struggled to cope with overcrowding.
"In the last year we have seen record levels of prisoner numbers, regular instances of the prison population exceeding capacity and daily use of police cells to deal with the overflow," he said.
"Our prisons are at breaking point."
South Australian Premier Jay Weatherill said to draw a link between Sunday's escape and prison overcrowding was simply nonsense.
He said escapes were very rare phenomena in SA.
