FRENCH conservative presidential candidate Francois Fillon urged his supporters not to “give up the fight” for the presidency despite corruption allegations dogging him.

A crowd of thousands chanted “Fillon, President!” at a rally in Paris yesterday seen as a test of whether he has enough backing to maintain his candidacy.

Fillon assailed former allies who have since abandoned his campaign, while support for him in opinion polls continued to plummet and elements in his Republicans party sought to oust him.

Once the frontrunner in the presidential race, Fillon is mired in a scandal over his Welsh wife Penelope's pay, and his campaign has been in serious trouble since he learned last week that he could be placed under formal investigation for misuse of public funds.

Party leaders prepared for a meeting today to discuss the crisis ahead of the March 17 deadline when all candidates must be formally endorsed by at least 500 elected officials.

A senior politician from Fillon's Republicans party had earlier said that several party heavyweights were about to issue a statement calling for former prime minister Alain Juppe, who lost to Fillon in November for the party ticket, to replace him.

As thousands of tricolore flag-waving supporters chanted for him to stay, Fillon laced his speech with attacks on the outgoing Socialist Government, the far-right National Front and the favourite, independent Emmanuel Macron.

After a string of resignations among advisers and backers, the 63-year-old Fillon had been banking on a big turnout to show his detractors he remains their best hope to win the presidency.

But others in his party are looking for a way to oust him.

“In the coming hours, we will propose an initiative,” Christian Estrosi, a close ally of former President Nicolas Sarkozy, told BFM TV. He said this would take the form of a statement from himself and other party heavyweights.

“We do not have the time to debate who has the most talent. The easiest thing obviously ... is the person who came second in the primaries and that quite simply is Alain Juppe.”

Jean Leonetti, a pro-Juppe lawmaker in the party said Sarkozy and Juppe had spoken on Saturday night and Juppe had probably outlined his conditions for replacing Fillon.

Calling for Juppe to take over, Jean-Christophe Lagarde, head of the centre-right UDI party, which has an alliance with the Republicans, said sticking with Fillon would lead to “certain failure.”

“In the Olympics when the gold medal winner is disqualified then it’s the silver medal holder that takes over,” Lagarde said on Europe 1 radio.

Fillon will appear on France 2 television’s Sunday evening news. A member of his staff said it would be an opportunity to “speak to the French.”

Opinion polls continue to show Fillon would fail to make the second round of the April/May election. Instead, Macron is consolidating his position as favorite to win a second-round head-to-head against far-right candidate Marine Le Pen.

An Ifop poll published on Saturday showed that more than 70 percent of French voters want Fillon to drop out. Support from his camp has also fallen to 53 percent from 70 percent two weeks ago.