PATNA - India's main opposition alliance split on Sunday, with the second-biggest party in the coalition pulling out after hardliner Narendra Modi was elected to lead the dominant party's 2014 election campaign.

The Janata Dal United (JDU) ended ties with the National Democratic Alliance - a federal coalition led by the Hindu nationalist BJP - saying it fears Modi's anti-Muslim image could alienate voters in next year's polls.

"We have decided to end the 17-year-old political alliance. It is important to walk away when there is a difference of opinion and political thought," Nitish Kumar, a senior JDU leader and chief minister of eastern Bihar state told reporters.

Controversial right-wing politician Modi was earlier this month named election committee chairman for the BJP ahead of polls scheduled for the first half of 2014.

Modi remains a hugely divisive figure nationally after being at the helm in Gujarat during religious riots in 2002 in which some 2,000 people - mainly Muslims - were killed.

Despite the split BJP leaders said Modi would still lead their election campaign in 2014.

"We made every effort to keep the alliance intact but the JDU seems to have its own political agenda," said senior BJP leader Sushil Modi, who is not related to Narendra Modi.

"The fact is that Narendra Modi is here to stay and political parties are scared of his rise."

India, the world's biggest democracy is currently governed by coalition at the federal level led by the Congress and several smaller parties that reflect regional aspirations, caste kinships and sectarian divides.