Leading figures in the ruling French Socialists have rushed to avoid a damaging split over their candidate in the spring presidential election, BBC News said.

Alarm bells sounded after Prime Minister Manuel Valls suggested he might stand against President Francois Hollande in party primaries.

A government spokesman warned Valls would have to resign in order to do so.

Meanwhile, Francois Fillon became the conservative candidate after triumphing in his party primaries on Sunday, November 27.

With nearly all the ballots counted, he had won 66.5% to 33.5% for his run-off rival, Alain Juppe.

A new opinion poll suggests he would easily beat the far right's Marine Le Pen in the actual election.

According to the Harris Interactive poll for French parliamentary TV (in French), Fillon would lead the National Front candidate by 26% to 24% in the first round, then win the run-off against her by 67% to 33%.

The same poll indicates that either Hollande or Valls would win just 9% for the Socialists, leaving them to trail both the far left and the centrists.