Seven people have died and more have been injured after a garment factory collapsed in Bhiwandi, Mumbai.

The incident happened at around 1am on Thursday at a two-storey building in the Shree Arihant complex collapsed in Bhiwandi, an area with many garment factories.

According to global union IndustriAll, a further 15 people are injured and four are still trapped.

Mumbai police commissioner Satyapal Singh admitted that the building was illegal and unauthorised construction was taking place.

The building was reportedly being extended, with some suggesting the collapse could have been caused by heavy monsoon rains, the Wall Street Journal reported.

"This illustrates that the problem of exploited workers labouring in unsafe buildings is not restricted to Bangladesh. The Bangladesh Accord is one step, but the concept must spread to other countries," said IndustriAll general secretary Jyrki Raina.