Heavy rains and winds unleashed by a cyclone over India's southeastern coast killed at least 42 people and damaged hundreds of homes, officials and news reports said Saturday.

Cyclone Thane struck Tamil Nadu state and the territory of Puducherry on Friday before weakening overnight, the India Meteorological Department said.

The storm smashed houses and downed power lines in four districts of Tamil Nadu, where 35 people were killed, said the state's top elected official, J. Jayalalitha.

The worst-hit district with 26 deaths was Cuddalore, about 170 kilometres south of Chennai, the state capital, he said in a statement, adding that winds reached 140 kilometres per hour.

About 20,000 people were evacuated to state-run relief camps from low-lying coastal areas in Cuddalore, Jayalalitha said.

The Press Trust of India news agency said seven other people were killed in and around Puducherry, which is also known as Pondicherry.