Polanski wouldn't be placed under house arrest in Switzerland before Monday, because he has yet to fulfill all the requirements to ensure that he stays in his chalet in the Swiss luxury resort of Gstaad, Justice Ministry spokesman Folco Galli said.
Galli did not elaborate, but the 76-year-old director must post $4.5 million bail, surrender his identity papers and be fitted with a monitoring bracelet.
Polanski cannot leave the house because the ministry is still deciding whether to extradite him to the United States for having sex in 1977 with a 13-year-old girl. Authorities in Los Angeles want him sentenced after 31 years as a fugitive.
Doubts over Polanski's whereabouts were answered Friday when the filmmamker's lawyer Lorenz Erni was seen entering and exiting a prison in the city of Winterthur, 26 kilometers (16 miles) northeast of Zurich.
Erni declined to speak to reporters after his 80-minute visit in the prison, where Polanski is being treated as an extradition detainee with more privileges than prisoners who have committed crimes in Switzerland.
A former Winterthur inmate said he was held in a cell next to Polanski, and that the director of such film classics as "Rosemary's Baby," "Chinatown" and "The Pianist" was given better treatment.
"For example, he could regularly call his wife or his lawyers," Yussi Akram told local Radio Top, adding that Polanski also chatted regularly with prison guards and could press an emergency button when he needed something.
Polanski always asked guards about their origins, and the prison authorities kept the filmmaker away from other inmates, Akram added.
"He sounded very exhausted," Akram said.
Zurich prison authorities and the Winterthur jail declined to comment.
The bail decision Wednesday was a major win for Polanski after a series of legal setbacks following his Sept. 26 arrest on a U.S. warrant as he arrived in Zurich to receive a lifetime achievement award at a film festival.
Polanski was accused of raping the girl after plying her with champagne and a Quaalude pill during a modeling shoot in 1977. He was initially indicted on six felony counts, including rape by use of drugs, child molesting and sodomy, but he pleaded guilty to the lesser charge of unlawful sexual intercourse.
In exchange, the judge agreed to drop the remaining charges and sentence him to prison for a 90-day psychiatric evaluation. The evaluator released Polanski after 42 days, but the judge said he was going to send him back to serve out the 90 days.
Polanski then fled the U.S. on Feb. 1, 1978, the day he was to be sentenced, and has lived in France since. He claims the U.S. judge and prosecutors acted improperly in his case, and his attorneys will argue before a California appeals court next month that the charges should be dismissed.
Swiss authorities have declined to say how they will transfer Polanski to his Gstaad chalet called "Milky Way," which has a stunning view of the surrounding Alps. The three-story home still appeared deserted Friday.