The move could lead to a revamped cabinet, a different coalition leader or the early election eagerly sought by right-wing opposition parties.

In a long-threatened move, former prime minister Renzi – who ruled from February 2014 to December 2016 – announced on Wednesday evening that ministers from his Italia Viva party would withdraw from the coalition, leaving Conte without a formal majority in the Senate.

Renzi said that how the crisis panned out from here was “up to the prime minister”.

“We are ready for all kinds of discussions,” he told a televised press conference in Rome.

The current government coalition is comprised of three parties: the populist Five Star Movement (M5S), the centre-left Democratic Party (PD) and Renzi’s smaller Italia Viva.

A leading member of the PD was quick to condemn Renzi’s move.

Former minister Andrea Orlando said it was “a serious mistake made by a few which we will all pay for”.

Without Italia Viva’s 18 senators, Conte will now need new friends in the Senate, although his majority is large enough in the lower house, the Chamber of Deputies.

Renzi has been criticising Conte for weeks over a range of issues but his attacks foused on the government’s €222 billion post-virus recovery plan, largely paid for in grants and loans from a €750  billion European Union fund.

Though there were concerns that Renzi’s protests would delay the recovery fund, Conte’s government received parliamentary approval for their plan on Wednesday.

Conte is reportedly resisting resignation, and is now trying to gather support for a new majority from small parties and independent candidates.

Conte signalled he wanted to take his fight for survival to parliament, with his main coalition partners backing plans to try to find so-called “responsible” members from among opposition ranks to prop up the administration.

On Monday he will address the lower house on the crisis when a likely fiery debate will be followed by a vote of confidence that should provide an indication of whether he can battle on.

If he survives that vote, an even tougher one will come the following day in the Senate, where cobbling together a majority looks more difficult.

For Conte to stay in office, he would need to find around 25 members in the 630-seat lower house and up to 18 in the 315-seat Senate.

However, such a majority would be fragile, making prolonged political stability hard to achieve.

If Conte or someone appointed by Italian President Sergio Mattarella to replace him can’t muster enough support in parliament, Mattarella could dissolve parliament, paving the way for an early election.

Polls indicate that an election could bring to power an alliance of right-wing and far-right nationalist forces.

Italy’s far-right League leader Matteo Salvini called on Thursday for a vote and shrugged off concerns about campaigning during the coronavirus epidemic, which has killed more than 80,000 people in Italy and plunged the country into its worst recession since World War II.