India's opposition Bharatiya Janata Party (BJP) has picked up support since naming Hindu nationalist Narendra Modi as its candidate for prime minister last month, but would need allies to form a government, two new opinion polls show.
The world's largest democracy is due to hold its largest ever general election within the next six months.
Modi, three times chief minister of the coastal state of Gujarat, was put forward by India's main opposition party in September, cementing the rise of a leader who many think is capable of turning round the economy but who remains tainted by deadly religious riots that broke out on his watch in 2002.
The ruling Congress party has led a coalition government for nearly a decade but is headed for its worst ever performance in a general election as it battles allegations of corruption and a sluggish economy, a survey by pollsters Team Cvoter for two television networks showed.
The survey forecasts the BJP to pick up 162 seats. The last Cvoter survey conducted in August, before Modi was named, forecast the party would get 130 seats, up from the 116 it now holds.
The Congress tally would drop to 102 seats from the 206 it now holds in the 545-member lower house of parliament if voting in the election were to reflect the poll, conducted for the India TV and Times Now networks and released late on Wednesday.
A coalition led by the BJP is expected to win 186 seats, meaning the BJP would have to find new allies among regional parties if it were to form a government. To rule, a party needs the support of 272 members of parliament.
The BJP and Congress are India's largest national parties but political power has shifted in recent years to smaller regional or state-level parties, making them kingmakers during coalition building and giving them more influence over policy.
Modi is credited with helping Gujarat's economy achieve average yearly growth in the double digits in the past decade and he is popular among many wealthy businessmen.
But he remains a polarizing figure, even within his own party, and some analysts believe he would struggle to cobble together a coalition.
A federal government beholden to regional parties with their own diverse agendas could be fragile and unwieldy, making it harder to manage Asia's third-largest economy, whose growth rate has already slowed to a decade low after a period of policy paralysis.
However, another opinion poll, released on Thursday, suggested the BJP could make major gains against regional rivals in India's northern heartland states of Uttar Pradesh and Bihar, home to a quarter of the population of 1.2 billion.
In Uttar Pradesh, which contributes more seats to parliament than any other state, the BJP will emerge as the largest party, ending years of dominance by two local politicians, the poll, carried out by Nielsen for the Economic Times newspaper, showed. It predicted 27 seats for the party out of 80 at stake, almost three times its tally in the last election.
Survey respondents said riots last month that pitted Hindus against Muslims in Uttar Pradesh, killing at least 50, were likely to consolidate Hindu votes behind the party.
Elections are notoriously hard to predict in India, which has very complex demographics.
The Cvoter study was based on a national sample of 24,284 randomly selected respondents. The data was collected between August 16 and October 15 - the period four weeks before and four weeks after Modi was declared as the BJP's candidate.
The Nielsen poll used a sample of 8,494 respondents, a mix of voters and opinion leaders, in rural and urban areas of two states. The data was collected between September 4 and September 26.
(Reporting by Malini Menon; Writing by Frank Jack Daniel; Editing by Clarence Fernandez)