A massive fire broke out during a fireworks display in a Hindu temple in south India early Sunday, killing more than 100 people and injuring at least 200 others, officials said.

The fire started when a spark from the unauthorised fireworks show ignited a separate batch of fireworks that were being stored at the Puttingal temple complex in Paravoor village, a few hours north of Kerala's state capital of Thiruvananthapuram, said chief minister Oommen Chandy, the state's top elected official.

Thousands had been packed into the temple complex when a big explosion erupted at about 3am, officials said. The blaze then spread quickly through the temple, trapping devotees within.

Most of the 102 people died when the building where the fireworks were stored collapsed, Chandy told reporters at the temple complex.

Local TV channels broadcast images of huge clouds of white smoke billowing from the temple, as fireworks were still going off in the night sky. Successive explosions from the building storing the fireworks sent huge chunks of concrete flying as far as half a mile, according to resident Jayashree Harikrishnan.

The temple holds a competitive fireworks display every year, with different groups putting on successive light shows for thousands of devotees gathered for the last day of a seven-day festival honouring the goddess Bhadrakali, a southern Indian incarnation of the Hindu goddess Kali.

This year, district authorities denied permission for the fireworks display, Chandy said.

The state's High Court had earlier mandated that fireworks must be stored more than 100 meters from temples - orders that were flouted at the Paravoor temple, said Loknath Behera, a top police official.

"We will be investigating how the orders were flouted and who was responsible for the decision to go ahead with the firework display," Chandy said.

Krishna Das, a resident of Paravoor village, said he had started walking away from the temple as the fireworks display was about to end when a deafening explosion followed by a series of blasts went off.

"I had been in the temple just a few minutes before watching the fireworks," Das said. He said he saw scores of people running away, chased by fire and chunks of concrete and plaster from the temple building.

Das said as soon as the first explosion was heard, a power cut hit the complex.

"It was complete chaos. People were screaming in the dark. Ambulance sirens went off, and in the darkness no one knew how to find their way out of the complex," he said.

He said that six ambulances had been parked outside the temple complex as a precaution. They were used to take the injured to hospitals in the nearby cities of Kollam and Thiruvananthapuram.

Local villagers and police pulled out many of the injured from under slabs of concrete.

Many of the buildings within a mile of the temple were damaged, with cracks in the walls or broken window panes from the impact of the explosion, Das said.

By morning, firefighters had brought the blaze under control, officials said. Rescuers sifted through the wreckage in search of survivors, while machines cleared the debris and ambulances drove away the injured.

As day broke, thousands of anxious relatives reached the temple in search of their loved ones. Many wept and pressed police officials and rescue workers for information on their family members.

Prime minister Narendra Modi, accompanied by doctors, was flying to Kerala to meet the survivors and victims' families.

At one of the main hospitals in Thiruvananthapuram, senior physician Thomas Mathew said that judging from injuries, a stampede was also likely to have occurred at the temple.

"There were few women or children among the injured. Most were men," Mathew said.