PARIS -- Former President Nicolas Sarkozy blasted the "lies, denial and impotence" of France's governing Socialists after estimates showed his conservative party and their allies chalked up wins across France in Sunday's local elections that saw the left lose half of its councils. The far-right National Front edged forward in its bid to create an army of grassroots support.

Socialist Prime Minister Manuel Valls conceded that the mainstream right won the voting.

"It is incontestable," Valls said, bemoaning divisions within the left that he said proved costly.

Polling firms estimated that Sarkozy's conservative UMP and centrist allies won 66 to 70 of the 98 local councils, while President Francois Hollande's divided Socialist Party -- which held the majority of local councils before the elections -- took up to 35 but potentially losing half of those it held before the elections. Last week's first round pointed to a win of the mainstream right.

Sarkozy, in a victory statement, said the right would prepare a changing of the guard "to redress the country, stop the decline that the most archaic socialism in Europe has plunged it into."

Estimates suggested the anti-immigration National Front could win up to two councils with scores that Valls said were "clearly in progression."

The political stakes were high despite the local vote as Hollande's left tried to save itself after failing to boost the lagging French economy or increase jobs and Sarkozy's right eyed a comeback, and each side tried to fend off the anti-immigration National Front which comes off a series of electoral victories.

The elections were a "critical step for the patriot movement on the road to power," National Front leader Marine Le Pen said. "The goal is near, reaching power and applying our ideas to redress France."

Valls had called on voters to choose anyone running, even a rival conservative, to block a National Front candidate, and he suggested the large victory by the right was partially because of his calls for solidarity against the far right. Sarkozy refused to reciprocate, telling supporters to simply abstain if a candidate from his UMP party wasn't running.

Valls said the French economy was showing signs of improvement, and vowed to march onward with his program.

"Jobs. Jobs. Jobs," Valls said, announcing plans for a new measure in the coming days addressing public and private investment.

Turnout was lower three hours before polls closed, measured at 41.94 per cent compared to 42.98 per cent in the first round, the Interior Ministry said.

Voters cast ballots to choose 4,108 local council members across the country for the 98 councils. Candidates appear on ballots in pairs -- one man, one woman -- to ensure that 50 per cent of council members are women.

Le Pen, who wasn't a candidate in the election but looked toward the 2017 presidential race, said Sunday that new council members would help win future elections, saying her party is the "only real opposition" to the powers that be in France.

Regional elections are set for December, and all parties are laying the groundwork for 2017 presidential voting.