A commuter steadies himself to negotiate flowing water while crossing a flooded road in Mumbai on Tuesday. AFP

Authorities in the Indian city of Mumbai issued a red alert on Tuesday and warned people not to venture out after heavy overnight rain in the financial hub brought flooding and travel chaos.

Some suburbs have seen more than 300 mm of rain in the 24 hours to Tuesday morning and more heavy rain is expected over the next two days, said India Meteorological Department (IMD) official K.S. Hosalikar.

Commuters wade past a stranded bus on a flooded road in Mumbai on Tuesday. AFP

The department issued a red alert for the city for the next two days and civic authorities advised people not to venture out unless absolutely necessary.

Trains, already running skeleton services due to the novel coronavirus lockdown, were suspended in several places because of flooding and traffic was disrupted on some of the city's main roads.

A landslide swept down a slope onto a main road in a northern suburb, media reported.

Commuters wade in waist deep water crossing a flooded road in Mumbai on Tuesday. Indranil Mukherjee/AFP

There was no impact on operations at Mumbai's airport apart from reduced visibility, a representative said.

The city struggles with the monsoon rains every year as widespread construction and rubbish-clogged drains and waterways make it increasingly vulnerable to flooding.

Mumbai is also struggling with a surging coronavirus outbreak with an average of 1,000 new cases being reported every day.