Marine Le Pen, France's far-right presidential contender, has compared a former close ally to a "slug," accusing him of sabotage as a succession of resignations shakes her party.

On Wednesday, French presidential candidate Marine Le Pen, the leader of the far-right political party National Rally, has accused one of its members, Nicolas Bay, of leaking confidential information to rival election candidate Eric Zemmour, according to media reports.

The party strongly condemned the "completely immoral behavior" of Nicolas Bay, regarding it as "sabotage."  

During a campaign event outside of Paris on Tuesday, Le Pen made a direct reference to Bay and other party leaders she suspected would join Zemmour's team, but delay their defection for political impact.

Le Pen called the strategy "that of the slug, not only because the slug is slow but because it's also sticky."

Stephane Ravier, the National Rally's only senator, joined Zemmour over the weekend, while European parliamentarian Gilbert Collard left in mid-January.

Bay, an MEP, and official RN spokesperson denied sending on any material to Zemmour, calling the claim "outrageous," in a Tweet.

In the coming days, he is anticipated to formally announce his intention to join Zemmour, an anti-Islam former TV analyst.

Referring to Bay's suspension, Le Pen's spokesperson Laurent Jacobelli asserted Wednesday that "Shaking a tree so that the rotten fruit falls is always a good thing to do."

The first voting round is scheduled for April 10 and President Emmanuel Macron currently leads the polls. Second place is contested by Le Pen, Zemmour, and right-wing contender Valerie Pecresse.

The top two candidates from the first round will face off in a run-off vote on April 24, which Macron is also expected to win.