By Stephen Brown

ROME, Feb 26 (Reuters) Italy's Romano Prodi looked likely today to garner enough support to win a vote of confidence this week and remain prime minister, with rebellious leftist allies sobered by the prospect of the right's return.

Coalition partners who pushed the nine-month-old government to the brink of collapse last week vowed to avoid more ructions that could propel conservative leader Silvio Berlusconi back to power. A vote is due on Wednesday or Thursday.

''The risk of making a gift to the right is too high for me,'' said communist leader Oliviero Diliberto, who only 10 days ago led a march against Prodi approving the expansion of a US base at Vicenza, as part of a wider revolt against foreign policy.

''The trauma of a crisis af ter nine months was useful as it made us all think about the consequences of Prodi falling,'' he told Corriere della Sera. ''If the alternative is a grand coalition or Berlusconi's return with early elections, well...'' The nine-party coalition, which ranges from Catholics to Greens and communists who have clashed over everything from the budget to gay rights and foreign policy, promised to abide by Prodi's list of 12 conditions for remaining at the helm.

Given a second chance by President Giorgio Napolitano, Prodi has to test his majority in parliament, where he is comfortable in the lower house but effectively level with the opposition in the Senate, which has 315 elected and seven lifetime members.

''RIGHT TO LIFE'' Prodi has now wooed one independent and one Christian Democrat, giving him 158 elected senators versus 156 for the opposition. The Speaker, who is from Prodi's bloc, traditionally does not vote.

Prodi has relied heavily on four lifetime senators since he took office in May after Italy's closest post-war election.

Another, seven-times prime minister Giulio Andreotti, will now back Prodi after he put a bill on rights for gay and unmarried couples on the back burner.

The bill is fiercely opposed by the influential Catholic Church, which fears it will introduce gay marriages by stealth.

''I will vote yes,'' said Andreotti, who abstained last week in the failed foreign policy vote which prompted Prodi's resignation. ''The government has the right to life as well.'' The gay rights bill was a surprise omission from Prodi's 12 conditions.

Few observers expect the far left in Prodi's coalition to remain docile for long.

Senate speaker Fausto Bertinotti, a communist who brought down Prodi's last government in 1998, reminded his comrades that while it was an ''important experience'' for the left to be in government, they should not lose sight of their ideals.

Some were puzzled by the about-face among Prodi's leftist allies.

''There's too much distance between the moderates and the far left. First they march in Vicenza, angry with Prodi, topple him, then what do they do? Defend him,'' said Luigi Pallaro, an overseas senator and wavering Prodi supporter.

''It's not serious,'' he said.

REUTERS SAM BST1933