A fire at a major Tata Electronics plant making Apple iPhones in southern India halted production on Saturday, as fire-fighting authorities tried to control the blaze, two people with knowledge of the situation said.

Tata Electronics said in a statement it was investigating the cause of the fire and would take necessary steps to safeguard the interests of its employees and other stakeholders.

"There has been an unfortunate incident of fire at our plant in Hosur, Tamil Nadu. Our emergency protocols at the plant ensured that all our employees are safe," a Tata Electronics spokesperson said in a statement.

Production was halted and employees were sent home for the day as a part of the factory was on fire, said a person with direct knowledge of the incident, calling the blaze "chemical-related".

The fire caused a building at the plant to collapse, although there were no reported casualties, a fire services official said.

It will take time to control the fire, which began in the morning in an area used to store chemicals, the fire official told Reuters on condition of anonymity, as he was not authorised to speak to the media.

The district's senior industrial safety official, J. Saravanan, said the authorities were investigating the cause of the fire. "We can't go inside now as the pathway is destroyed. It will take one day for it to cool down," he told Reuters.

More than 10 fire and rescue vehicles were trying to control the situation at the spot, the Hindu newspaper reported.