Supporters pose with a cut-out of Hindu nationalist Narendra Modi, the prime ministerial candidate for India's main opposition Bharatiya Janata Party (BJP), at a temple in the western Indian city of Ahmedabad May 15, 2014. [Photo/Agencies]

The 63-year-old's promises of job creation and clean, efficient government resonated with many of the half a billion people who braved blistering summer heat to vote in the world's biggest election over the last five weeks.

Since being named as his party's candidate last September, Modi has flown 300,000 km and addressed 457 rallies in a slick, presidential-style campaign that has broken the mould of Indian politics.

Modi's media-savvy, modern campaign ran circles round his slow-footed rival, Rahul Gandhi, 43, from the Congress party. The Congress, which led India to independence from Britain, was headed for its worst-ever result after two terms in office marred by corruption and a floundering economy.

Prime Minister Manmohan Singh, who as finance minister launched reforms in 1991 that brought an end to decades of economic isolation, has already bid farewell to his staff after ten years in office marked by mounting policy paralysis.

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The desire for change has been so strong that voters put aside concerns about Modi's Hindu-centric politics. A dark chapter of violence against Muslims on his watch has mattered less and less to many, including a bulging middle class alarmed by dwindling purchasing power and job opportunities as the economy slumped to sub-five percent growth in the last two years.

Gandhi was leading by a slender margin in his seat of Amethi, a family bastion that has been held in turn by his uncle, father and mother, Sonia. A loss there would spell disaster for the great grandson of India's independence leader.

The alliance led by the BJP was winning in 332 seats of the 543-seat parliament, counting trends showed. The BJP alone looked set for an absolute majority, with 278 seats.

Responding to the news Indian markets got off to a roaring start, with the rupee breaking below 59 to the US dollar, an 11-month high, and the benchmark stock index jumped 6 percent before paring its gains.

Betting on a Modi win, foreign investors have poured more than $16 billion into Indian stocks and bonds in the past six months and now hold over 22 percent of Mumbai-listed equities - a stake estimated by Morgan Stanley at almost $280 billion.

Modi has promised that, if elected, he would take decisive action to unblock stalled investments in power, road and rail projects to revive economic growth.

Tax and labour market reforms, backed by a gradual opening up to foreign investment, would seek to create the 10 million jobs that Asia's third-largest economy must create every year to employ young people entering the workforce.

Modi watched the results on TV at his home in Gujarat, and was due to meet his mother, 95-year-old Hiraben, soon after results become clear.

"My blessings are there. The country will develop. My blessings are there," she said.

He was later expected to embark on a victory tour to his local constituency of Vadodara, while party workers in New Delhi hoped he would later fly to New Delhi for what could be a hero's welcome.