Polanski won an Oscar in 2002 for The Pianist
Film-maker Roman Polanski has been denied bail ahead of his possible extradition to the US, the Swiss Justice Ministry has said.
Ministry spokesman Folco Galli said the government maintained there was a high risk Polanski may flee if released from custody.
Polanski is being held in Switzerland over his 1977 conviction for unlawful sex with a 13-year-old girl.
He left the US in 1978 before he could be sentenced and has never returned.
Polanski was detained in Switzerland on 26 September as he travelled from France to collect a lifetime achievement award at the Zurich Film Festival.
"In our view, there is still a very high risk that he will flee and that a release on bail or other measures after a release cannot guarantee Polanski's presence in the extradition procedure," Mr Galli said.
Polanski's legal representatives are also asking Switzerland's highest criminal court to free Polanski.
Mr Galli said the Justice Ministry has submitted a letter to the tribunal explaining why it opposes release.
The arrest of Polanski, who won an Oscar in 2002 for The Pianist, a harrowing story of Nazi-occupied Warsaw, has prompted an outcry among some politicians and Hollywood heavyweights.
But last week, California Governor Arnold Schwarzenegger said the film-maker should not get special treatment because he is a "big-time movie director".
A petition has been signed by film-makers including Pedro Almodovar and Stephen Frears, and actors including Monica Bellucci and Fanny Ardant, expressing dismay at Polanski's arrest.
Other Hollywood luminaries, including film producer Harvey Weinstein, have called for Polanski's release.
His victim, Samantha Geimer, sued Polanski in December 1988, alleging sexual assault, infliction of emotional distress and seduction.
The film-maker agreed to pay her $500,000 five years later.
But in January this year Ms Geimer asked a US court to drop charges against Polanski, saying the continued publication of details "causes harm to me, my husband and children".