Indian Prime Minister Narendra Modi's ruling alliance will be just a few seats short of a majority in parliament, bolstered by a rise in nationalist sentiment over hostilities with arch foe Pakistan, a survey showed on Monday, days before voting begins.

About 900 million people are eligible to vote in the election starting on Thursday, in which Modi's Bharatiya Janata Party (BJP)-led group is taking on the Congress and its allies and a clutch of regional parties.

The election had become tighter because of discontent in the countryside over a weak rural economy and lack of jobs for young people. But over the last month, support for Modi's Hindu nationalist party has grown following a spike in tension with Pakistan, the polls say.

The BJP and its allies are expected to win 267 of the 543 parliament seats at stake, the CVoter polling agency said, just five short of the halfway mark required to rule.

The latest estimate is down sharply from the alliance's current tally of 330 seats secured when Modi swept to power in 2014, promising to transform Asia's third-largest economy.

Modi ordered air strikes in February on the suspected camp of a militant group based in Pakistan that had claimed responsibility for a deadly car bombing in disputed Kashmir, dramatically ratcheting up tension with the neighbouring nation.

Pakistan sent war planes into Indian Kashmir the next day and the two nuclear-armed foes engaged in their first air duel in decades.

“In the immediate aftermath of the Balakot strikes the percentage of those strongly satisfied with the government rose to a recent all-time high of 52 per cent,” CVoter said, referring to the raid in Pakistan's Balakot area.

A second poll by India TV-CNX pre-poll said Modi's alliance would clear the halfway mark, winning 275 seats.

Modi has made his strong stance on national security a key part of the BJP's election campaign.

On Monday, the party said it would scrap decades-old special rights for the people of Indian-occupied Jammu and Kashmir so as to integrate the state more closely with the rest of the country, a move the party's base has long sought.

Political leaders in occupied Kashmir have warned that repealing the law could trigger unrest. Held Kashmir's special constitutional status prevents outsiders from buying property in the state, among other restrictions.