The Spanish parliament's lower house is debating whether to end Prime Minister Mariano Rajoy's nearly eight years in power and replace him with the leader of the Socialist opposition.

Rajoy refused to resign after his conservative Popular Party was fined as beneficiary of a large kickbacks-for-contracts scheme. In a damaging ruling last week, the court questioned Rajoy's claim that he and other top officials were unaware of the party's illegal accounting.

Socialist leader Pedro Sanchez, who is leading the no-confidence vote against Rajoy, would instantly become the country's prime minister if he wins 176 or more votes in the 350-seat Congress of Deputies on Friday.

His opening speech Thursday proposing an alternative government will be watched by other opposition lawmakers who are still undecided on whether to oust the government.