One of France's most dangerous gangsters, known for brazen attacks on cash-in-transit vehicles, on Saturday blasted his way out of jail after taking several wardens hostage, officials said.

Redoine Faid, who risked a heavy sentence over the 2010 death of a policewoman, used explosives to blast through five prison doors and break free in the northern town of Sequedin.

Police and helicopters were trying to track the 40-year-old, who set fire to his getaway car in the south of the city of Lille before getting into a second vehicle.

State Prosecutor Frederic Fevre said Faid, who had already been France's most wanted a few years ago, was a "particularly dangerous prisoner" and was still armed and in possession of explosives.

Fevre said Faid had four hostages with him during the jailbreak. One was released just outside the prison, another a few hundred metres away and then the final two were left along a highway.

Wardens unions described the prison break as "an act of war" and also argued that the Sedequin jail was inadequate for such dangerous convicts.

"This escape and hostage-taking were methodically prepared," the CGT union said, complaining that searches on detainees were not thorough enough.

A woman who was visiting her imprisoned son described the chaos caused by Faid's spectacular escape.

"I thought my last hour had come. Suddenly, everything started blowing up. The walls started shaking, as did the windows and the doors. I was really scared," Rose Lafont said.

Prison union leader Etienne Dobremetz said Faid had received a visit from his wife earlier on Saturday morning.

Contacted by AFP, her lawyer vehemently denied any suspicion of involvement in her husband's escape.

"It happened very quickly, it was clearly very well organised, we are still busy putting the facts together," a local administrative official said.

Faid is also known for co-authoring a book in 2010 upon his release on parole after a decade in prison for robbery, about his delinquent youth and rise as a criminal in Paris' impoverished crime-ridden suburbs.

He said his life of crime was inspired by American films such as 'Scarface' and 'Heat' -- in which actor Robert de Niro carries out an armoured car heist.

After his first robbery, Faid, of Algerian extraction, fled to Israel where he wore the Jewish skullcap and picked up Hebrew to blend in.

Despite vowing he had turned his back on crime Faid was in 2010 suspected of being the mastermind of an armed robbery in which a young policewoman was killed in a shootout.

Faid, nicknamed Doc, landed back in prison in 2011 for failing to comply with his parole conditions and was due to serve the remaining eight years of his original sentence.

He faced 30 more years over the policewoman's death however.

"I wasn't surprised when I heard about his escape although there were no signs that anything was in the works," his lawyer Jean-Louis Pelletier told AFP.

He described his client as an extremely intelligent and well connected person.