Prosecutors in New York are believed to be planning to drop the charges against Dominique Strauss-Kahn within the next fortnight.

According to an investigator quoted by the New York Post, the sexual assault charges are set to be dropped by July 18, in the wake of questions over the credibility of the hotel maid who accused him.

The former leader of the International Monetary Fund said he planned to counter-sue a French writer if she filed a criminal complaint accusing him of attempted rape.

Tristane Banon announced yesterday that she would take legal action over a 2002 incident. She said she had been moved to do so because she found it "unbearable" to see Mr Strauss Kahn, who was released from his bail conditions last week, "no sooner free than eating in a luxury restaurant with friends".

"I want to be heard," added Ms Banon, who has previously said that she was dissuaded from pressing charges at the time because of her mother's political links to Mr Strauss-Kahn. "Perhaps, finally, there's a chance I will be listened to."

But Mr Strauss-Kahn, who has always maintained his innocence with regards to the chambermaid's allegations, described Ms Banon's claims as "imaginary" and vowed to sue for defamation if she proceeded.

His comments came after a poll revealed that more than half of French people believed Mr Strauss-Kahn had no political future. Before he was arrested in May he was widely tipped as a viable rival to Nicholas Sarkozy at next year's French presidential election.