Lawyers for film director Roman Polanski have filed an appeal to ask for a special investigation into alleged judicial and prosecutorial misconduct in the fugitive director's 32-year-old sex case.

Lawyers have not only accused the current US prosecutors of giving false information to Swiss authorities, to speed Polanski's extradition to the United States, but have also suggested that the original prosecutor in Polanski's 1977 trial tried to disqualify the judge in the case, but was ordered by superiors not to do so.

The lawyers also said current prosecutors knew Polanski's potential sentence does not fall within Swiss requirements for an extradition order.

The appeal claims US prosecutors were aware that the now-deceased judge intended for Polanski to serve no more than 90 days in prison when the director pleaded guilty to unlawful sex with a 13-year-old girl.

Swiss authorities have said they will extradite Polanski only if they know he will be sentenced to at least six months behind bars.

Prosecutors in Los Angeles are believed to be readying to try to block the appeal.