The logic of Berlusconi's positions "escapes me" and "I couldn't accept his offer," Monti said, drawing chuckles.
Monti praised his government and Parliament for its support of spending cuts, new taxes and pension reform that he said had saved Italy from succumbing to the debt crisis.
"Italians as citizens can hold their heads up high in Europe," Monti said, noting Italy had avoided the kind of bailouts that Greece, Portugal, Ireland and Cyprus have been forced to take.
Italy's President Giorgio Napolitano dissolved Parliament after Monti handed in his resignation following approval of the country's national budget law. Monti noted that as a senator-for-life, he remains in Parliament and thus doesn't need to run for a seat in the legislature.
Napolitano set elections two months before their expected date, recognizing that without Berlusconi's support for Monti, it was useless to wait until late April for Italians to go to the ballot box.
Voter opinion polls indicate a centrist ticket backing Monti would take about 15% of the vote, meaning any government headed by him would have to have the support of either of Italy's largest political groupings: the center-right, led by Berlusconi, or the center-left, led by Pier Luigi Bersani.