Smoke rises after caught fire and collapsed in Peera Garhi area in New Delhi on Thursday. Manish Swarup/AP

A New Delhi factory collapsed on firefighters on Thursday as they tackled the third major blaze in the Indian capital in less than a month, officials said.

Firemen hailed as heroes in Delhi horror blaze

Fourteen people, mainly firefighters, suffered injuries and one remained trapped inside the battery factory seven hours after the alert was raised, an emergency services spokesman said.

Emergency services have been put on special alert following a series of high profile disasters in recent weeks.

People watch firemen in action after a factory caught fire and collapsed in Peera Garhi area in New Delhi. AP

A fire official said three people were rescued from the debris of the building in Peera Garhi area in western New Delhi. Thirty-five fire engines were at the site, and the rescue operation was continuing for some people feared trapped there.

An eyewitness told New Delhi Television news channel he heard an explosion around 5am and the fire station reported the structure collapsed soon afterward.

Fire that tore through a bag factory on December 9 killed 43 people, while nine others died in a later incident.

The fire official spoke anonymously because he was not authorised to release the information.

There were no workers inside the building when the fire broke out around 4am, the police said.

The fire officials received injuries during the rescue work, the police said. They have been hospitalised.

A Delhi Fire Service truck is parked next to the site of a fire and building collapse at a factory in New Delhi. AFP

The blaze was extinguished, but a heavy smoke engulfed the rear portion of the building which collapsed. It contained inflammable material like acid and plastic used for making batteries, the police said.

Poor safety standards are a frequent cause of fires in India.

More than 150 firefighters were called to the factory in the Peeragarhi district of Delhi after the alert was raised just before dawn on Thursday. Flames more than 10 metres (33 feet) high were reported.

Firefighters were battling the blaze inside when an explosion rocked the back of the factory which collapsed into a heap of debris giving off black toxic smoke.