(BANG) -Roman Polanski has reached a bail agreement with Swiss authorities.

The veteran film director had his offer of $4.5 million bail accepted, which should allow him to be released from prison and kept under house arrest at a ski chalet he owns in the resort of Gstaad.

However, the Swiss Justice Ministry is considering appealing against the bail conditions at the country's Supreme Court - meaning he currently has to remain behind bars.

Polanski, 76, presently faces extradition to the US from the European country, where he was arrested on September 26, over a conviction for having sex with a 13-year-old girl in 1977.

Justice Ministry spokesman Folco Galli said: "We have ten days to appeal, but will come to our decision quickly."

Galli said the reason for appealing was because 'The Pianist' director is considered a "high flight risk" and may flee back to his home in Paris.

Judges in Geneva were reportedly swayed in granting the bail offer because of Polanski's family circumstances. The director's lawyer Herve Temime said his wife and two children are currently suffering the most because of the high-profile case. He added that they are "very upset psychologically by this separation that is a true heartbreak for them".

In 1977, Roman pleaded guilty to charges of having underage sex with 13-year-old Samantha Gailey, now known as Samantha Geimer.

He believed he would face a jail term of just 42 days, and claimed a judge had reneged on a plea bargain deal to reduce the charges from rape and serious sexual assault if he admitted under-age sex. However, on the day of his sentencing he fled to London then Paris.

France does not have an extradition treaty to the US, so if he escaped over the boarder he would be safe.