Friday's announcement comes a week after Berlusconi lost his comfortable absolute majority in parliament, when Gianfranco Fini, a long-time ally, split from Berlusconi's People of Freedom party.
Fini, a co-founder of the party, has set up a breakaway faction in parliament that could deprive Berlusconi of his majority.
The prime minister's new platform is expected to include reforms of justice and the tax system, along with a devolution of power to regional governments and economic aid to the impoverished south.
On Wednesday, Berlusconi passed the first major test since the split with Fini when Italy's lower house rejected a no-confidence motion against Giacomo Caliendo, a junior justice minister under police investigation for alleged influence-peddling.
Fini and Berlusconi split after bickering for months on a number of issues, including morality in politics in the wake of scandals hitting coalition members.
Fini has taken a harsher stance than Berlusconi, demanding that public officials suspected of corruption resign.
Last week, Berlusconi accused Fini of mounting an opposition from within and working against the government, effectively expelling him from the party.
Fini says his politicians will support the government when it carries out the joint electoral platform under which the coalition was voted into power in 2008.
But he says they will oppose it when they consider its policies unjust or against the common good.
Berlusconi has issued reassurances that his government, whose term is due to end in 2013, is stable.