Montreal: Three inmates deemed extremely dangerous by police have escaped from a Canadian jail in a helicopter, the second such daring prison break recently in Quebec.

In March 2013, two inmates were lifted on a hijacked helicopter from a prison north of Montreal. They were both quickly re-arrested, along with the two accomplices.

Police are now asking for the public's help in tracking down Yves Denis, 35, Denis Lefebvre, 53, and Serge Pomerleau, 49 - all accused of mafia ties - after the Saturday night jailbreak in Quebec province.

"The helicopter landed in a courtyard at the detention centre," police spokeswoman Ann Mathieu told the French news channel RDI on Sunday.