At least 79 people died in two separate overnight bus accidents in the flooded southern Indian state of Tamil Nadu.

In one incident, at least 49 bodies were pulled from a flooded stream in Perumalkoil village in Thanjavur district, about 300kms south of state capital Chennai, formerly known as Madras.

The dead include 22 women and seven children.

The accident occurred when the bus driver tried to cross an overflowing causeway across a jungle stream.

The bus rolled into the stream and was swept away for 15 metres. Firemen used cranes and ropes to pull it out.

Yesterday, at least 30 passengers of another bus died when the vehicle was swept away in flash floods in Ramanathapuram district, about 450km south of Chennai.

Tamil Nadu has been lashed by heavy rains over the past few days due to a deep depression over the Bay of Bengal.

In badly hit Cuddalore, Tiruchirapalli and Karur districts, over 200,000 people have been displaced over the last couple of days.