Cairn said it had made "a potentially significant oil discovery" in Rajasthan in the north west of the country, its third such find this year.

The new field has an estimated reserve of 400 million barrels, Cairn said.

Cairn's share price has more than doubled this year since the first discovery was announced in January.

The first find, in the Mangala field, has estimated reserves of between 450 million and 1.1 billion barrels of oil.

Last month, Cairn announced a smaller find of between 130-470 million barrels.