A PARIS employment tribunal yesterday rejected former Societe Generale trader Jerome Kerviel's plea for a new expert inquiry to help overturn his dismissal in France's biggest-ever trading scandal in 2008.

In a separate criminal case, Kerviel is running out of options to escape conviction and a jail sentence upheld by an appeals court in October over 4.9 billion euros (US$6.4 billion) in losses that French bank SocGen said were the result of unauthorized trades by Kerviel.

The 36-year-old ex-trader, who was ordered to repay the huge sum in its entirety, has never denied masking the 50 billion euros in market positions that went wrong as the financial crisis unfolded in early 2008. He has, however, always said his bosses knew what he was doing, an accusation SocGen denies.

Kerviel has asked the tribunal to overturn his dismissal and grant him 4.9 billion euros in damages but no new inquiry will be opened.

Speaking to supporters and media outside the courthouse after the hour-long hearing, an unshaven and tieless Kerviel said he was disappointed but would keep fighting ahead of a final ruling by the tribunal, which could take months.

"I am disappointed, of course ... They've refused (my demands)," he said. "We will keep going."

Far-left groups and the popular press in France have painted Kerviel as a naive victim of big finance, despite his role before the case as a highly-paid trader. Dozens of supporters chanted slogans against SocGen and threw fake banknotes like confetti outside the court, also brewing coffee and serving croissants to the crowd.

SocGen's legal team issued a short statement saying Kerviel had been late in submitting several demands and that after a "lengthy debate" the tribunal had rejected them.

Without a new inquiry, it is unlikely there will be any new elements brought to light that might help Kerviel's case.