Italy's opposition leader Silvio Berlusconi has said his centre-right coalition will support Romano Prodi's government in a vote on Afghanistan.
Berlusconi has extended his support to the embattled Prodi
Parliament is to decide whether to extend funds to keep Italy's 1,800 peacekeepers in Afghanistan until 2011.
Mr Prodi, the prime minister, offered to resign 10 days ago after communists in his own coalition voted against his foreign policy.
Mr Berlusconi said Italy had to send a clear political message to its allies.
Some senators in his coalition had threatened to abstain to bring down the centre-left government.
"We will vote for the re-financing of the Afghan mission because we're a country that must act seriously and we must send a clear political message to our allies," Mr Berlusconi said.
Mr Prodi has given Afghan President Hamid Karzai assurances that Italy will stick to its key commitments.
But the Communist parties in his coalition are still opposed to the idea and with a vote on the re-financing of the mission still to be approved by 1 April, the mission was in doubt, says the BBC's Christian Fraser in Rome.
On Wednesday, Mr Prodi won a confidence vote in the Senate, saving his coalition and allowing him to continue in office.
But his reliance on the opposition illustrates the fragility of his own coalition, our correspondent says.
On Friday, the PM will face another vote of confidence in the lower house, where he has a large majority and is expected to win.
All nine parties in the coalition have signed up to a binding agreement on the government's policies, but there are still disagreements on several key policies.