Authorities say addicts at the Christ is Love centre were kept 'like prisoners.' (Juan Contreras/Associated Press)

A fire swept through a two-storey private rehabilitation centre for addicts in a poor part of Peru's capital city Lima on Saturday, killing 27 people and critically injuring five as firefighters punched holes through walls to rescue residents locked inside.

The "Christ is Love" centre for drug and alcohol addicts was unlicensed and overcrowded and its residents were apparently kept inside "like prisoners," Health Minister Alberto Tejada told The Associated Press.

Authorities said 26 people died at the scene, and prosecutors spokesman Raul Sanchez said Saturday night that one of six men hospitalized in critical condition died later.

Peru's fire chief, Antonio Zavala, said most of the victims died of asphyxiation. All the victims appeared to be male.

The local police chief, Clever Zegarra, said the cause of the 9 a.m. fire was under investigation.

"There has been talk of the burning of an object, of a mattress, but also of a fight that resulted in a fire. All of this is speculation," he told the Associated Press. "I've been here at the scene from morning to evening but for the moment the exact cause of the fire is not known."

One resident of the centre in Lima's teeming San Juan de Lurigancho district said he was eating breakfast at 9 a.m. local time on the second floor of the center when he saw flames coming from the first floor, where the blaze apparently originated.

Gianfranco Huerta told local RPP newsradio station that he leapt from a window to safety.

"The doors were locked, there was no way to get out," he told the station.

Associated Press journalists at scene said all the windows of the building they were able to see were barred. Journalists were not allowed inside as police cordoned off the block. By early afternoon, all bodies had been removed from the centre.

Most of the bodies seen by reporters were shirtless, their faces blackened. Many were also shoeless.

"This rehabilitation center wasn't authorized. It was a house that they had taken over... for patients with addictions and they had the habit of leaving people locked up with no medical supervision," Tejada said.

Authorities said they did not know how many people were inside the centre at the time of the fire. They said they were looking for the centre's owners and staff, some of whom apparently fled the scene.

Had to cut through metal doors

Zavala said the fire was of "Dantesque proportions." Firefighters had to punch a hole through a wall with an adjoining building to help the people trapped inside the rehabilitation centre.

"We've had to use electric saws to cut through the metal bars of the doors to be able to work," Zavala said.

Relatives of residents of the centre gathered in front of the building weeping and seeking word of their loved ones.

One of them was Maria Benitez, the aunt of 18-year-old Carlos Benitez, who she said was being treated at the centre.

"I want to know if he is well or not... his mother sent him here to rehabilitate him because he used drugs," she told ATV television.

Local media reported that the "Christ is Love" rehabilitation centre sought to use Biblical teachings to help treat addicts.

Peru's fire fighters are notoriously underfunded. All the South American country's firefighters are volunteer and the annual firefighting budget for the entire country is $19 million US.