The two allies - the Union of Christian Democrats and the New Italian Socialist Party - are putting pressure on conservative Berlusconi to resign and form a new government, a tactic past Italian prime ministers have used to strengthen faltering coalitions.
Berlusconi's popularity is fading amid concerns over a weak economy and Italy's continued presence in Iraq.
The coalition is still smarting from a defeat in regional elections two weeks ago.
Asked whether he might assemble a new government, the media mogul-turned-politician responded: "Let's wait and see."
"If the country's interests must prevail, I will make the most appropriate decisions," Italy's Ansa news agency quoted him as saying.
In his typical joking manner, he added: "Anyway, you're not going to get rid of me so easily."
Berlusconi was planning to meet President Carlo Azeglio Ciampi after an evening meeting with his coalition allies.
Berlusconi did not say whether
he would resign
He said later on Friday that he was supported by most of his coalition allies, but refused to divulge whether or not he would resign.
"I am a responsible person. I am concrete, and I don't let myself get distracted by things that aren't concrete," Berlusconi said.
In the 3-4 April regional vote - widely seen as a test of the government's popularity a year ahead of general elections - Berlusconi's coalition lost 11 of the 13 regions that were up for grabs.
Several analysts said he faced little choice but to try to form a new government to regain lost ground before next year's vote.
Berlusconi's dissatisfied allies want an upheaval, "a sign of discontinuity", said Gianfranco Pasquino, a political science professor at the University of Bologna.
"They want to send to voters a signal of change, of significant change," Pasquino said.
The New Italian Socialist Party, which had two minor sub-Cabinet-level posts, also said it was withdrawing from the coalition.
"They want to send to voters a signal of change, of significant change"
University of Bologna
A bigger concern is Berlusconi's largest partner, the National Alliance. Gianfranco Fini, another deputy prime minister and also foreign minister, on Thursday demanded that the government submit its platform to parliament for a confidence vote.
A vote of no confidence would force Berlusconi to resign and topple the government.
Though Berlusconi appeared to waver, he had insisted in the past that he was determined to serve his full five-year term until 2006.