Four detainees have escaped from a prison in Berlin, breaking out part of a concrete wall and climbing over a barbed-wire fence, authorities said.

The men had reported for work at a workshop in Ploetzensee prison before their escape.

They broke a concrete pillar between two ventilation gaps, climbed through the hole and then over the nearby fence, city justice ministry spokesman Michael Reis told news agency dpa.

Footage from a camera trained on a nearby gate showed the four men climbing through the hole shortly before 9am, authorities said.

The fence appeared to be undamaged. The alarm was raised more than half an hour later.

The men had convictions for theft, burglary and bodily harm, among other things.

All arrived at the prison this year. Three were due for release next year and the fourth in 2020.

The prison has 362 inmates.