A Pennsylvania appeals court ordered a temporary halt to the sexual assault case against comedian Bill Cosby on Tuesday pending its ruling on whether defence lawyers' appeal of a decision moving the case to trial can be quashed.

The order by the Pennsylvania Superior Court postpones a March 8 preliminary hearing in a suburban Philadelphia court where Cosby, 78, faces charges of sexually assaulting a woman more than a decade ago.

Cos by's attorneys had appealed a ruling by Common Pleas Court Judge Steven O'Neill in Norristown that dismissed the entertainer's claims that he had been granted immunity from prosecution in the case.[nL2N15I136] Prosecutors had sought to quash the appeal.

Cos by's attorneys had asked the judge to toss the charges, contending that a deal reached with former Montgomery County District Attorney Bruce Castor spared their client from prosecution in exchange for a 2005 civil deposition.

In the deposition, Cosby admitted giving what he said was an anti-allergy drug to his alleged victim, Andrea Con stand, before a sexual encounter that he described as consensual.

Con stand, now 44, has said Cosby plied her with alcohol and drugs before raping her.

More than 50 women have accused Cosby, whose long career was based on family-friendly comedy, of sexually assaulting them in attacks dating back to the 1960s. Many of the incidents are too old to prosecute.

The Pennsylvania case is the only incident for which Cosby has been criminally charged.