But it remains to be seen if the government will collapse. On Tuesday, the opposition stepped up calls for Mr. Berlusconi to resign, but he can fall only if he loses his parliamentary majority, and for now his party loyalists are sticking with him.

“With Berlusconi, the rules from any other place or government don’t apply,” said Mario Calabresi, the editor of the Turin daily newspaper La Stampa. “It’s hard to know if this will really be the last scandal that makes Berlusconi fall, because for him to fall, someone has to bring him down.”

On Tuesday, Mr. Berlusconi said he would not resign. He said he was less the target of a judicial investigation than of “subversive” media attacks.

Indeed, splashed across the press, the wiretapped conversations have gripped Italy. Culled from a range of women, lawyers and associates, the wiretaps show the intersection of politics and the kind of reality-television culture that Mr. Berlusconi has helped create in his decades as Italy’s largest private broadcaster.

In one wiretapped conversation published Tuesday in La Repubblica, Ms. Mahroug said the prime minister had offered to pay her to keep quiet about her detention for theft. “He called me, telling me, ‘Ruby, I’ll give you as much money as you want, I’ll pay you, I’ll cover you in gold, but the important thing is that you hide everything; don’t tell anyone anything.’ ”

The scandal has a cast of characters that would fill an entire soap opera season. Also under investigation are Emilio Fede, 79, one of Mr. Berlusconi’s oldest friends and the director of a news program owned by his company, Mediaset; and Lele Mora, 55, an agent for television personalities. The authorities are also investigating Nicole Minetti, 25, a former dental hygienist and now a politician for Mr. Berlusconi’s party in Lombardy, who is accused of helping manage the young women in Mr. Berlusconi’s orbit, including intervening with the local police when Ms. Mahroug was questioned about a theft last May.

Prosecutors say the three helped procure attractive young women, many of whom had appeared on the reality television shows that have been a staple on Mr. Berlusconi’s television channels for years, for parties at Mr. Berlusconi’s villas.