At least 10 people were killed and several others seriously injured in an explosion in a steel factory in southeastern India, officials have said.

"Ten people died in the blast on Wednesday evening and about nine are battling for their lives in hospital," Lav Agarwal, district administrator of Visakhapatnam in the state of Andhra Pradesh.

"We found people with 75 per cent burns who were rushed to the hospital," a spokesperson for the Vizag Steel plant said. "An oxygen supply pipe burst and we are investigating."

The spokesman said that first reports suggested that the explosion occurred in a control room, but that the cause of the blast was uncertain.

According to local media reports, the cause of the explosion was a fire at the recently commissioned oxygen plant in the steel-melting unit, which completely gutted the plant as flames swept through the unit.

Reports said nearly 30 workers and top plant officials were inspecting the equipment when the blast occurred.

Witnesses said the explosion was so powerful that cars parked outside the unit were flung in the air.

The death toll was expected to rise because the condition of some of the injured was critical, Police Commissioner Purnachandra Rao said.

He said at least 16 people were injured, many of them critically.

The 41-year-old state-owned plant is one of India's major steel producers. The plant has been expanding over the past four years, with the addition of new units that were expected to nearly double its current capacity of 3.5m tonnes.

Also called the Rashtriya Ispat Nigam Limited (RINL), the plant is situated in Visakhapatnam, 600km from state capital Hyderabad.

This is the third fire incident in less than two months.

Source: Agencies