NEW YORK • Bill Cosby's lawyers, who suffered a setback after their request to delay his trial by three months was rejected, are now taking aim at the judge.

They want him to step down from the comedian's upcoming molestation retrial, alleging the judge is biased because his wife works with sexual assault victims.

Cosby's legal team is headed by Mr Tom Mesereau, a celebrity Los Angeles lawyer who got the late pop star Michael Jackson acquitted of child molestation charges in 2005.

"Mr Cosby respectfully requests that the court recuse itself from these proceedings to avoid the appearance of a conflict of interest, and that the matter be reassigned," read a memorandum sent to Agence France-Presse by the comedian's spokesman.

The petition said there was "a clear appearance of partiality" as a result of the marriage between Judge Steven O'Neill and his wife Deborah, a social worker at the University of Pennsylvania's office of counselling and psychological services.

She coordinates a sexual trauma outreach and prevention team and wrote her dissertation on acquaintance rape.

The defence said she had also apparently donated money to an activist group that had targeted Cosby.

The motion was filed in Norristown, Pennsylvania, after the judge ruled last week that five additional women who claim to have been sexually assaulted by Cosby can testify.

At the first trial, which collapsed when the jury failed to reach a unanimous verdict, he ruled that only one other accuser could take the stand.

Jury selection is set to begin on April 2. The June 2017 trial irrevocably damaged the once towering icon of US popular culture, best known for his role as a father and obstetrician on 1984-92 TV series The Cosby Show.

The 80-year-old is accused of drugging and molesting a former university basketball official at his home in 2004.

AGENCE FRANCE-PRESSE