A lawyer for Dominique Strauss-Kahn said Thursday he had no proof of a conspiracy over the former IMF chief's arrest in New York last May, challenging talk of a plot to smear his client.

Suggestions of a political conspiracy against Strauss-Kahn, once the runaway favourite to become France's next president, began soon after his arrest on suspicion of attempted rape.

But Henri Leclerc, a member of Strauss-Kahn's legal team in Paris, criticised the speculation which has resurfaced since new accounts purporting to describe the circumstances surrounding his arrest were published.

I have no proof there is a conspiracy, Leclerc told Europe 1 radio, adding that he denounced the partial truths being circulated in the French media.

The UMP party of President Nicolas Sarkozy has dismissed allegations, raised in the New York Review of Books, that private messages from Strauss-Kahn were being read in the party's Paris offices before his arrest.

A book by Strauss-Kahn's French biographer, Michel Taubmann, added fuel to the speculative chatter.

Strauss-Kahn, a former socialist finance minister, was forced to resign his IMF post and bow out of French public life after he was arrested and held on bail in New York, accused of trying to rape a Guinean hotel maid.

New York prosecutors later dropped criminal charges against him, citing doubts about the credibility of the maid, Nafissatou Diallo, who is now pursuing Strauss-Kahn in a civil case.

French prosecutors recently shelved an investigation into separate accusations by a Parisian writer of attempted rape.

However, Strauss-Kahn came under scrutiny yet again in October after his name appeared in an investigation into a prostitution ring that supplied women to clients of the luxury Carlton hotel in Lille, northern France.

Eight people have been arrested, including Carlton managers, businessmen and a local police commissioner as part of an official inquiry into the network.

French construction firm Eiffage also dismissed an executive whom investigators suspect of using company funds to supply prostitutes to associates and to pay for the women to travel to Paris and Washington to take part in sex parties with Strauss-Kahn.

Using prostitutes is not illegal in France.

However, Leclerc said Strauss-Kahn believed he was taking part in swingers parties and had no reason to suspect that the women present were prostitutes.

People are not always clothed at these parties. I challenge you to tell the difference between a nude prostitute and a classy lady in the nude, Leclerc said.

(Reporting by Thierry Leveque, writing by Nick Vinocur; editing by David Stamp)