Far-right French presidential candidate Marine Le Pen has denounced accusations that she misappropriated European Union funds as "dirty tricks."

Sunday saw potentially explosive revelations that prosecutors are examining a report by the EU's anti-fraud agency accusing the National Rally leader and colleagues of misusing more than $650,000 USD.

Le Pen is currently trailing incumbent Emmanuel Macron by around 10 percent in weekend polls, ahead of the election run-off on April 24.

French news platform Mediapart has published a section of the EU anti-fraud body OLAF's 116-page report. This accuses Le Pen and three other former MEPs -- including both her estranged father Jean-Marie and former partner Louis Aliot -- of misusing European Parliament funds.

None are accused of profiting directly, but of claiming EU funds for staff and event expenses.

The report alleges that Le Pen personally misappropriated around $148,000 USD of public money from the body while an MEP between 2004 and 2017.

Speaking a day after the revelations, at a country visit to a Normandy market, Le Pen took aim at her accusers.

"I obviously absolutely dispute these accusations of which I have not been aware, which already poses a problem in terms of the rule of law, of which I have not been provided with any proof, any element, despite the requests that I was able to do," she said.

She added: "The dirty tricks of the European Union, a few days before the second round, I am very used to that and I think that the French are absolutely not fooled."

A European Parliament official told AFP the body intends to "proceed to recover the sums unduly paid."

The Paris prosecutor's office has confirmed that it is studying the OLAF report which it received on March 11.

National Rally president Jordan Bardella said his party has filed two legal complaints against OLAF, and will be lodging a third in response to the report.

Speaking to BFM TV, Le Pen's lawyer Rodolphe Bosselut said his client had yet to be questioned and that neither he nor Le Pen had seen the OLAF report.

Bosselut told AFP that OLAF's investigation has been open since 2016 and that Le Pen was questioned by post in March 2021. She has faced an ongoing investigation since 2017 over suspicions of employing fictional party assistants in the European Parliament.

Sunday's election is predicted to be far closer than that of 2017 when Macron defeated Le Pen by a two-to-one margin.