PARIS (Reuters) - Seven out of 10 French voters want conservative presidential candidate Francois Fillon to step down, an opinion poll showed on Friday, as the scandal over alleged “fake work” by his wife continued to blight his campaign.

Francois Fillon, a former French prime minister, member of The Republicans political party and 2017 presidential candidate of the French centre-right, attends a campaign visit in a CSU, urban surveillance center, in Athis Mons Paris suburb, February 8, 2017. REUTERS/Thomas Samson/Pool

Among rightwing voters, 53 percent want him replaced, the poll by Odoxa for France Info radio showed. That figure includes people who said they would vote for the far-right National Front (FN). Excluding FN voters, it was 36 percent.

Fillon has apologized to the French people over the way hundreds of thousands of euros in taxpayers’ money were paid to his wife over many years, but has said the work she did was genuine and that he did nothing illegal.

He has vowed to continue his campaign for the April election, despite losing his position as favorite to centrist rival Emmanuel Macron, and called the affair a plot by his political opponents. His lawyers are contesting the legitimacy of an official investigation into the payments.

Fillon was elected to stand for his The Republicans party in a November primary.

He beat off the challenge of better-known candidates by presenting himself as an honest politician who would cut back on government spending.

His showing in polls has slumped in the two weeks since the “fake work” scandal broke. On Thursday, another poll showed his popularity rating had slid to 18th place from third. Macron held on to first place.

TARTUFFE

The original allegations were made in the satirical weekly le Canard Enchaine on Jan. 24 and the saga has been frontpage news ever since.

Thursday’s edition of the weekly L’Obs magazine showed a mocked-up photograph of Fillon wearing a 17th-century wig and entitled “Tartuffe” - the name of a play by Moliere about a hypocrite.

Opinion polls show Fillon coming third in the first round of voting on April 23, behind Macron by a few percentage points, and with far-right National Front leader Marine Le Pen coming first.

The French electoral system puts the top two candidates from the first round into a runoff against each other. Polls show either Macron or Fillon winning a runoff against Le Pen comfortably.