At least 31 people were killed in floods and heavy rain in India's southern state of Tamil Nadu this week, a top federal minister has said, as rescuers struggle to reach scores still stranded in high waters.

Heavy rains have paralysed several districts of the state, inundating entire neighbourhoods, roads and railway tracks, days after a cyclone hit India's south-eastern coast, causing widespread damage.

"The (toll) number could change," federal Finance Minister Nirmala Sithraman told reporters on Friday, adding that more than 40,000 people have been rescued so far and efforts are underway to reach those still stranded.

The state is one of the major electronics and manufacturing hubs in India. Some southern neighbourhoods remained waterlogged on Friday.

Abnormal precipitation

"We're struggling to get tractors and boats with food and essentials through water in the worst-affected areas," said M. Balamurugan, who and other volunteers have been distributing food and essentials.

Tamil Nadu recorded over 64 millimetres of rainfall this week, more than triple the 20 millimetres that would be normal at this time of year, the weather department said, predicting more rainfall in parts of the state over the next five days.

For some the floods are reminiscent of rains eight years ago in state capital Chennai that killed 290 people and inundated large swathes of the city.