Italy's Northern League cool on Berlusconi alliance

Italy's former Prime Minister Silvio Berlusconi gestures as he speaks during a news conference at Villa Gernetto in Gerno near Milan October 27, 2012.

ROME (Reuters) - Silvio Berlusconi will have to withdraw his bid for a fifth term as Italy's prime minister if he wants to seal a vital alliance with his former coalition partners in the Northern League, the head of the regionalist party was quoted as saying on Wednesday.

"Dear Silvio, we can't agree to it if you're in the field. The League cannot support you if you keep up your candidacy for prime minister," Roberto Maroni was quoted as saying in the daily La Repubblica newspaper before a meeting with Berlusconi late on Tuesday.

An accord between Berlusconi's People of Freedom (PDL) party and the League is considered vital to the centre-right's bid to prevent the centre-left Democratic Party (PD), which is leading strongly in the opinion polls, from forming a stable government.

Under Italy's complex electoral laws, the PD is expected to win a strong majority in the Lower House but may struggle to capture the Senate, which is elected on a local basis, with individual battles in each region.

In past elections, the left has struggled because of its traditional weakness in the richer and more populous northern regions including Lombardy and Veneto, where there are more Senate seats than in the less well-populated south.

A deal between the PDL and the League could give the centre-right a chance of winning enough seats in the north to prevent PD leader Pier Luigi Bersani from forming a stable government.

On Tuesday, Berlusconi said he was still negotiating with the Northern League, which has been struggling to emerge from a corruption scandal which toppled its founder Umberto Bossi, a long-time ally of Berlusconi.

Maroni, interior minister in the Berlusconi's last government, has always been less close to the 76 year-old media magnate and he said the position he had taken reflected strong resistance among grass-roots League voters.

He said the line "completely interprets the feelings of our members, officials and parliamentarians."

(Reporting By James Mackenzie; Editing by Jon Boyle)