Distraught relatives have been identifying the dead

After speaking to survivors a judge ordered Omar Chaban to be detained, but he has not yet been formally charged.

At least 714 people were injured - 102 critically - in the fire, which seems to have been started by a flare.

Officials said the tragedy was made worse because emergency exits were locked to stop people sneaking in.

"Because of greed, a lot people who could have been saved lost their lives," said Buenos Aires Mayor Anibal Ibarra, according to Reuters.

The government has declared three days of mourning and ordered all nightclubs closed for New Year's Eve.

'Choking smoke'

The fire began late on Thursday night at the Cromagnon Republic, in Once district, as rock band Los Callejeros was playing to the mostly young crowd.

Investigators say they believe the fire started when a group of concert-goers set off a flare, which set sound-proofing material on the ceiling alight.

Many victims died from smoke inhalation, city officials said.

Bodies were lined up on the pavement outside the club Tragedy in pictures

"People fired the flares into the ceiling, which was made of cloth and rubber," 15-year-old Cecilia Arce told reporters, according to AFP news agency.

"The rubber started burning, but with few or no flames, making a terrible smoke that choked you, killed you, if you breathed it."

Other survivors described a frantic stampede to escape.

Exits were "locked with chains and padlocks", said Mayor Ibarra. Concert-goers managed to force open some exits, but only firefighters were able to break open the others.

A government minister also blamed overcrowding for the fire, one of Argentina's worst disasters. Local media said the club had a permit to hold 1,500 people but that up to 4,000 people may have been inside at the time.

TV pictures early on Friday showed bodies being lined up on the pavement outside the club and parents screaming and wailing as they arrived to look for their children.

Distraught relatives also gathered outside the city's hospitals, where lists of the dead and injured showed most victims were in their teens or 20s.

Rescue workers reportedly said at least 12 young children were among the dead.

"I'm looking for my 20-year-old brother. I have his picture and I don't know if it will help but I don't know what else to do," said Monica Alegre, sobbing outside the morgue, Reuters reported.

Other parents demanded the hospitals release their children's bodies for burial.