Roman Polanski remains in jail while the Swiss Justice Ministry decides whether to appeal a court's offer to grant him bail of $4.5 million US. (Michael Euler/Associated Press)

A Swiss court says it is willing to release Polish-American filmmaker Roman Polanski on bail of $4.5 million US.

But the Swiss Justice Ministry still could appeal this decision to the country's highest court.

"We will decide quickly on whether to order his release or file an appeal with the Federal Tribunal," Justice Ministry spokesman Folco Galli said Wednesday after the ruling of the lower court was released.

That means Polanski, who is wanted in the U.S. on a 1977 sexual assault conviction, remains in jail for now.

Later Wednesday, Swiss Justice Minister Eveline Widmer-Schlumpf said she sees "no reason" to appeal the court decision allowing Polanski's release on bail.

On Wednesday, the Swiss Criminal Court said it would release Polanski if he remains under house arrest in his Swiss chalet and wears electronic monitoring.

The court said it still considers the director of Rosemary's Baby a flight risk, but thought the $4.5-million US bail offer — which was made using his Paris apartment as security — enough to reduce that risk.

"The 76-year-old appellant is married and the father of two minors," the court said. "It can be assumed that as a responsible father he will, especially in view of his advanced age, attach greater importance to the financial security of his family than a younger person."

Polanski is in a Swiss jail awaiting extradition to the U.S. since being arrested Sept. 26 while in Switzerland for a film festival.

In 1977, he pleaded guilty to having sex with a 13-year-old girl, but fled the United States on the eve of his sentencing because he believed a judge might impose a longer term than agreed in his plea bargain.

With files from The Associated Press