Controversial Hindu nationalist Narendra Modi headed for a landslide election win in the Indian state of Gujarat on Thursday, firming up his chances of running for prime minister in 2014.

A decade after overseeing India's worst religious riots since independence, Modi was set to be re-elected as chief minister in a win that seals his status as the most high-profile leader of the right-wing Bharatiya Janata Party (BJP).

Supporters of the BJP, which is the main opposition party in the national parliament, chanted and waved flags in delight as official counting put the party ahead in 116 seats with the rival Congress party leading in just 60.

While victory was expected, Modi's popularity on the national stage remains tempered by his failure to stop the riots in his home state in 2002. Some 2,000 people were killed in clashes between Hindus and Muslims, most of them Muslims.

One of his former ministers was jailed for life for instigating the killing of 97 Muslims in one of the most notorious episodes of the riots. But all investigations have cleared Modi of any personal responsibility.

Gujarat, which has a population of 60 million, is one of India's fastest-growing and most pro-business states, but it was badly scarred by the unrest.

"He has proven (today) that he has the ability to showcase himself as a prime ministerial candidate," Sebastian Morris, a professor at the Indian Institute of Management in Ahmedabad, Gujarat's main city, told AFP.

"Congress will have to work hard to check his increasing clout."

Though he has never openly declared his ambition to be prime minister, Modi is seen as angling to lead the BJP into the 2014 national elections -- with the ruling Congress party weakened by slowing growth and corruption scandals.

Loyalists on Thursday held up banners declaring that Thursday's victory was only "a trailer" ahead of the 2014 elections.

But many in the BJP itself are wary of Modi, fearing that he remains a hate figure for Muslims and secularists following the riots, some of the worst unrest in post-independence India.

Modi, who has been chief minister since 2001 and is seeking a fourth term, is blamed by some rights groups for turning a blind eye as mobs went on an orgy of violence with victims set alight or hacked to death in the streets.

"Big success in one state does not mean that the party is ready to put Modi centre stage," Pralay Kanungo, of the Centre for Political Studies at Jawaharlal Nehru University in Delhi, told AFP.

"The big challenge for him is appease his party and potential allies. He will have to fine-tune his political skills to be the BJP candidate in 2014."

Modi campaigned in the state polls on a platform of economic expansion and investment, gathering votes from a broad range of farmers, small businesses and young people attracted by his strong personal style, analysts said.

Modi, who is still denied a US visa since the 2002 riots, avoided Hindu nationalist themes on the campaign trail.

Congress received some good news in the Himachal Pradesh state which also went to polls, where it was forecast to throw out the BJP.