France's far-right National Rally (RN) could be headed for an absolute majority in the upcoming parliamentary elections, a top pollster said Thursday.

Brice Teinturier, deputy director of the Ipsos polling group, told AFP that the far-right RN was showing a strong trend with a solid electorate behind it.

Three days before the first round of voting on June 30, polls suggest President Emmanuel Macron's centrist alliance will come third behind the RN and the New Popular Front (NFP) left-wing coalition.

RN chief Jordan Bardella has insisted he will only accept to be prime minister and lead a government if it wins an absolute majority of the 577 seats in the National Assembly after the July 7 second round.

The latest Ipsos poll published in Le Monde newspaper said that the RN would win 36 percent of the vote, the NFP left-wing coalition 29% and Macron's alliance just 19.5.

The RN has "a deep, strong dynamic. We have an electorate there that seems solid to me and it is leading the race," Teinturier told AFP in an interview.

Teinturier, one of France's highest-profile polling gurus who regularly appears on TV, said Ipsos was not making projections of seats before the first round as the figures risked being unreliable.

But he said the RN's high polling numbers will give it an "extremely powerful advantage" heading into the second round which sees run-offs in constituencies where there was no outright winner the first time round.

The RN "can not only envisage a relative majority, but we cannot exclude, far from it, an absolute majority," he said.

Teinturier said the situation showed a political landscape that "had not shifted much" since European elections earlier this month.

In that vote, Macron's alliance was trounced by the far right, prompting him to call the snap legislative elections.