Spanish lawmakers have agreed to subject Prime Minister Mariano Rajoy to a vote of no confidence this week.
It comes in the wake of graft convictions of businesspeople and officials tied to his conservative Popular Party (PP).
The lower house of Spain’s parliament, the Congress of Deputies, said it would hold a debate on Thursday on whether Mr Rajoy should be replaced by Socialist leader Pedro Sanchez, and then vote on the opposition’s no-confidence motion on Friday.
All major parties except for the ruling PP are calling for Rajoy to step down, but the prime minister has fended off the pressure until now.
He called the opposition’s campaign “opportunist” and said instability goes against the general interest of Spain’s people.
Mr Sanchez has yet to enlist enough support to defeat Mr Rajoy with an absolute majority of the 350 seats in the fragmented chamber.
The Socialists have the backing of the far-left, anti-establishment Podemos party, but they would need votes from lawmakers with the pro-business Ciudadanos (Citizens) party or nationalist and separatist parties for their leader to supplant Mr Rajoy.
Ciudadanos, a rising star in the center-right of Spanish politics led by Albert Rivera, a young lawmaker from Catalonia, is refusing to support Mr Sanchez and is seeking a new general election instead.
Recent polls have given Mr Rivera’s party strong chances of placing first in an election, positioning him to become prime minister, but without winning a majority to form a government on its own.
Mr Rivera stepped up the pressure Monday on Mr Rajoy to step down even though Ciudadanos refuses to support the Socialist candidate.
“There is a minority government that is alone and holding on to power, with a prime minister that is not reacting,” Mr Rivera told journalists.
Spain’s National Court last week convicted 29 people, including PP supporters and elected officials, on charges of fraud, tax evasion and money laundering, among other crimes.
The court also fined the governing party 245,000 euros (£214,200) for benefiting between 1999 and 2005 from “an authentic and efficient system of institutional corruption” that provided PP officials with bribes from business owners in exchange for public infrastructure contracts.
Judges also found evidence a slush fund helped finance the party and questioned the sincerity of Mr Rajoy’s testimony denying knowledge of the scheme.
Neither PP, which is appealing the verdict, nor Mr Rajoy were defendants in the case, but the prime minister had to testify as a witness.