NEW DELHI (AFP) - Mr Rahul Gandhi on Sunday forecast a bigger win for India's ruling Congress party in next month's elections than it secured last time, rejecting comments by senior party members that they face an uphill battle.

Mr Gandhi, frontrunner to be prime minister should Congress win, predicted the party would surpass its tally of seats secured at the 2009 national elections, rejecting opinion polls showing it headed for a humiliating loss.

Acknowledging that after a decade in power, "there is a certain amount of anti-incumbency against us", Mr Gandhi disagreed with Finance Minister P Chidambaram that Congress was the "underdog".

"Congress is fighting a challenging election and we will win the election," Mr Gandhi told the Press Trust of India in an interview. "I am not a soothsayer but we will do well," he told PTI.

Although he declined to predict the number of seats, Mr Gandhi said the figure would be higher than the 206 Congress won in the 543-seat national parliament in 2009, when it formed a coalition government.

Mr Gandhi also hit out at arch rival Narendra Modi, widely tipped to win the elections, claiming he still has many questions to answer about his links to deadly riots in the western state of Gujarat where he is chief minister.

Mr Gandhi said there was a "clear and inexcusable failure" of governance in Gujarat where more than 1,000 people, mainly Muslims, were killed in riots in 2002 after Mr Modi took office in 2001.

"The specific allegation and evidence pointing to Mr Modi's responsibility in the 2002 riots are yet to be adequately probed. Any talk of his having been given a clean chit (slate) may be politically expedient, but is far too premature," he said.

"There are many unanswered questions. There is a lot more the country needs to know."

Mr Modi has denied wrongdoing and has been cleared by legal inquiries, but allegations that he failed to stop the riots continue to dog the prime ministerial candidate.

Hindu nationalist Modi and his opposition Bharatiya Janata Party are expected to come to power on a platform of economic revival following the world's biggest elections starting on April 7.

The elections have pitted Mr Gandhi, vice president of Congress and scion of India's political dynasty, against Mr Modi, the son of a tea-stall owner.

Voting will take place in nine phases until May 12 with counting and results expected four days later on May 16.