A poll by BVA of voting intentions gave Fillon between 18 and 20 percent of the vote in the April 23 first round, behind far-right leader Marine Le Pen with 25 percent and independent centrist Emmanuel Macron with 21-22 percent.

A poll by Ifop Fiducial on Friday night showed a similar slide in support for Fillon since a scandal involving payments to his wife emerged in late January.

A recent poll by Harris Interactive showed that 69 percent of French people wanted Fillon to drop his bid to become the country's president.

Fillon told reporters on Friday that he would fight what he called a "demolition exercise."

Macron the new favorite?

Emmanuel Macron - the former protege of President Francois Hollande - is now favorite for the presidency. 

Macron last year created a new political party called "En Marche" ("On the Move"), on a centrist, liberal economic and pro-European platform.

By electing Benoit Hamon, France's Socialists meanwhile appear unlikely to make much impact in the race.

Marine Le Pen - leader of the far-right National Front - would lose to Macron in the May 7 knockout by 34 percent to his 66 percent, the BVA poll found.

If Fillon did get through to the runoff against Le Pen, surveys suggest she would lose, with 40 percent of the vote to his 60 percent.

The election will be staged in April and May of 2017, taking place across two rounds. If no one receives more than 50 percent of the vote in the first round, the two candidates with the highest share of the vote proceed to a second round of voting.

J'accuse

"Le Canard Enchaine," a satirical newspaper, reported on January 25 that the former prime minister had paid his wife Penelope (left) 830,000 euros ($900,000) for work for him that she did not appear to have done.

Police sources say two of Fillon's childrenare now implicated in a payment scandal.

Sources close to the investigation said on Wednesday they were trying to establish whether the embattled conservative candidate paid large sums of money to two of his children.

Fillon has insisted that Marie and Charles Fillon "were lawyers" for "specific assignments" when he was a senator.

French prosecutors are seeking to determine whether there are grounds to suspect embezzlement and misappropriation of public funds, which could see Fillon formally charged.

jbh/gsw (Reuters, AFP)