They lived rent-free in the estate and the billionaire politician gave them large sums of cash in return for sex, reports the Independent.
Milano Due was one of the first gated housing estates in Italy, a sprawling complex of flats set in landscaped gardens, built by Berlusconi himself in the 1970s when he was a thrusting young property developer.
With underground parking, a supermarket, bars and other facilities, it is one of the most fashionable addresses in the Milan hinterland.
When he moved into television, Berlusconi located the headquarters of Mediaset, his television company, here.
But it is alleged that in his declining years the estate has also become the headquarters of what is, in effect, his harem.
Corriere della Sera newspaper revealed its presence in yet another blow to the battered image of the Prime Minister as he prepares to defend himself against what could be the gravest crisis of his political career.
Prosecutors in Milan are demanding that he be put on trial immediately for having sex with an underage prostitute.
Karima El Mahroug, a teenage belly-dancer from Morocco who trades under the name of Ruby Rubacuori, revealed the existence of the flats.
