The head of Cairn Energy's Indian subsidiary said its key discovery in Rajasthan was now expected to produce oil at a much faster rate after it went on stream quicker than scheduled.

Rahul Dhir, chief executive of Cairn India, said the company had submitted a revised report for the Mangala field to regulators in which it forecast output of 125,000 barrels per day.

That compares with an original plan of around 100,000 bpd.

While the company has not increased estimates of reserves, the revised plan holds out the prospect that Cairn India will realise the gains from its huge investment in Rajasthan faster than expected.

This will provide a boost for the company's Edinburgh-based parent. Cairn Energy retained a 69% holding in the Indian subsidiary after it floated on stock exchanges in that country last year.

Cairn India expects to have Mangala onstream in 2009.

It forecasts production from Mangala and three other fields in Northern Rajasthan will eventually plateau at 150,000 bpd.

The fields are expected to produce for 25 years.

Cairn India owns 70% in the Rajasthan block, while state-owned Oil and Natural Gas Corporation has the remaining 30%.