Four ministers resigned from the Italian government yesterday, escalating a political crisis in Prime Minister Silvio Berlusconi’s coalition that could last for weeks.

The four – Europe Minister Andrea Ronchi, Deputy Economic Development Minister Adolfo Urso and two junior ministers – are supporters of Speaker of Parliament Gianfranco Fini, a former ally of Mr Berlusconi turned rival.

Mr Fini’s Future and Freedom movement announced the pull-out in a statement.

“We propose a new government, a new majority, a new agenda for reform... Berlusconi is holing himself up in his palace like in a bunker,” Mr Urso said in an interview on the news channel SkyTG24 ahead of the announcement.

Italo Bocchino, a spokesman for Mr Fini’s Future and Freedom movement, said in an interview with La Stampa daily that there should now be a national unity ­government without Mr Berlusconi that could include the centre-left ­opposition.

“We have to look without prejudice and an open mind to the opposition, which should be brought into a national unity government,” he said.

Mr Berlusconi “is the least qualified to be the head of a national unity government. He always needs an opponent to unify his forces,” he added.

A fifth government official, Giuseppe Maria Rina – a junior minister for transport – also submitted his resignation in solidarity with the rebels even though he does not belong to Mr Fini’s movement, his spokesman said.

Mr Fini called on Mr Berlusconi to resign this month and threatened to pull ministers loyal to him out of the government if the Prime Minister did not.

Mr Berlusconi has fought back, vowing to hold confidence votes in Parliament and to fight off his rivals in parliamentary elections if needed.

Mr Fini said yesterday that Italy’s ruling class had “lost its sense of dignity, of responsibility of duty that people in public office should have”.

Italy’s main political forces agreed this weekend that any confidence vote in Parliament would only come after lawmakers approve a budget for 2011 at a tricky time for heavily-indebted Italy on international financial markets.

Debate on the budget is set to start today in the lower house but final approval by the upper house may come only later in November or in December and the centre-left opposition says it fears “time-wasting tactics” by Mr Berlusconi. Despite the political wrangling expected in the coming days, the consensus among experts is that Mr Berlusconi’s government – in place since 2008 elections – will eventually fall long before its mandate runs out in 2013.

The crucial question is what exactly will happen after that.

Among the scenarios outlined in recent days are: a new Berlusconi government with a different coalition; an interim technocratic ­government with a different Prime Minister; and a centre-left government supported by Mr Fini.

Experts agree that, sooner or later, early elections need to be held.

Mr Berlusconi’s popularity has plunged and he has been under pressure from a series of scandals – including a row over his role in a police inquiry on a 17-year-old nightclub dancer who said she attended some of his parties.

But he remains a formidable politician.

A poll published in Corriere della Sera on Saturday gave his People of Freedom party the highest proportion of voting intentions – 26.5 per cent.

It was followed by the centre-left Democratic Party at 24.2 per cent; the populist Northern League party, the junior coalition partner in government, with 11.8 per cent; and Mr Fini’s Future and Freedom movement at 8.1 per cent.