By Barry Moody
ROME (Reuters) - Former Italian Prime Minister Silvio Berlusconi on Monday announced an alliance with the devolutionist Northern League which could prevent the center-left forming a stable government after elections next month.
Berlusconi has been striving for weeks to seal the deal with his estranged former allies to strengthen the center-right bloc, under a strategy to stymie the center-left government which is expected to emerge from a February 24-25 election.
The League had previously refused a pact because of rank-and-file opposition to the scandal-plagued Berlusconi being candidate for prime minister. The media magnate was driven from office a year ago at the height of Italy's economic crisis after he was charged with having sex with an underage prostitute.
In an interview on Italian radio station RTL, Berlusconi left the issue of the premiership open in a future center-right government. He said he would prefer to be the economy minister and that mostly likely Angelino Alfano, secretary of his People of Freedom (PDL) party, would be prime minister.
However he said he would remain head of the PDL and the coalition. "It will be the head of the coalition who would indicate who will be the prime ministerial candidate if we win," said Berlusconi who had previously insisted he himself would be the candidate.
Berlusconi said he had struck the deal early on Monday with Roberto Maroni, leader of the League - which was part of his previous coalition government. There was no immediate comment from the League but Maroni was due to give a news conference later on Monday.
The center-left led by Pier Luigi Bersani has been ahead in opinion polls for months. The latest survey, published on Sunday, said it would win between 38 and 39 percent.
A PDL-League alliance could pull in about 28 per cent of the vote with a centrist alliance under outgoing premier Mario Monti on 14-15 percent, the poll showed.
Under Italy's much-criticized electoral law, Bersani is expected to win a comfortable majority in the lower house.
But in the Senate the distribution of seats is decided on a regional basis and the populous northern regions led by Lombardy return more senators.
By allying with the League in its northern strongholds, Berlusconi hopes to be able to stymie a center-left government in parliament.
The League wants strict controls on immigration and favors giving more power and autonomy to Italy's 20 regions. It wants more tax revenue to go directly to the regions, saying the rich north is picking up the tab for a south it brands as corrupt and economically backward.
Berlusconi said that under the deal the PDL would support Maroni as candidate for president of Lombardy in regional elections.
The former prime minister is awaiting a verdict expected soon in the trial in which he is accused of paying an underage prostitute. Weakened by the scandal, he was forced out of office and replaced by Monti in November 2011 when Italy tottered on the edge of a Greek-style debt crisis.
He has become notorious for almost daily changes of position, which Monti called "bewildering" when he entered the electoral campaign in December.
Berlusconi's party backed Monti's technocrat government for a year before precipitating its fall by withdrawing support last month.
Berlusconi previously suggested Monti could lead the center-right but since the former European Commissioner sided with centrists has launched vitriolic daily attacks on him especially for his introduction of a widely hated property tax.
Industry Minister Corrado Passera, frequently touted as a possible election candidate before Monti entered the field, on Monday criticized Monti's electoral platform for being too timid on reforms.
In an interview with the Corriere della Sera daily, the former head of Italy's biggest bank also said the outgoing premier should not have allied himself with two existing centrist parties.
(Additional reporting by Philip Pullella and Jennifer Clark; Editing by Pravin Char)
(c) Copyright Thomson Reuters 2013. Check for restrictions at: http://about.reuters.com/fulllegal.asp