It was the first public comment by the 74-year-old leader since he was indicted Tuesday on charges he paid for sex with a 17-year-old Moroccan girl and then used his influence to cover it up.
He spoke shortly before holding talks and a working dinner with Russian President Dmitry Medvedev, his first international meeting since the indictment.
Berlusconi has denied any wrongdoing, dismissing the accusations as "groundless" and the case as a "farce" and a "shame." He has accused prosecutors of trying to topple his government.
On Wednesday, the premier dodged questions about the case during a news conference on economic themes in Rome and, in contrast with recent days, did not go on the offensive to defend himself.
"Out of love of my country, I won't talk about this," Berlusconi told reporters. "I can only say one thing: I'm not worried at all."
Berlusconi also avoided the topic in remarks before a meeting with Medvedev, focusing instead on the close ties between Russia and Italy.
"I believe that I am a point of reference for Russia within the European Union, and I have personally tended to all of the relations that the EU has and will develop with the Russian federation," Berlusconi said, emphasizing his close personal friendships with Medvedev and Russian Prime Minister Vladimir Putin.
The prostitution trial starts April 6 before three female judges - an ironic twist for the premier. Italian women staged nationwide protests last week contending that the scandal and Berlusconi's view of women is degrading to female dignity. The three judges were picked at random.
The indictment marks a serious challenge to Berlusconi's grip on power at a time when the premier is weakened by an acrimonious split with an ex-ally. It reignited calls for Berlusconi's resignation, with the opposition contending the scandal - with allegations of wild parties at the premier's villas with scantily clad women - has embarrassed Italy and damaged its image abroad.
"A premier who is a defendant, who spends his days disputing the magistrates, is undoubtedly a man with no time to govern, and probably with no authority to do so effectively," a leading political analyst, Stefano Folli, wrote in Wednesday's financial newspaper Il Sole 24 Ore.
The abuse of influence charge carries a prison sentence of four to 12 years, and if Berlusconi is sentenced to more than five years, he would be barred from ever again holding public office. The child prostitution charge carries a possible prison term of six months to three years.
Even if found guilty, it is unlikely he would ever go to prison. The appeals process would take years, and in Italy people over 75 rarely serve time.
Berlusconi's deepening legal woes also test his crucial alliance with the Northern League, which he relies on for a majority in parliament.
While other Berlusconi allies quickly came to his defense, Northern League leaders mostly kept silent about the indictment, which observers read as a sign of unease.
Berlusconi met with League leader and government minister Umberto Bossi and other party officials on Tuesday night.
"We are as united as ever, and determined to continue the legislature until its natural end," Berlusconi told reporters Wednesday.
He was elected in 2008. The next parliamentary elections are scheduled in 2013.