MADRID (Reuters) - Spanish Prime Minister Pedro Sanchez faces growing pressure from within his Socialist Party to call an early election, before scandals besetting his four-month-old minority government undermine a surge in voter support.

Spain's Prime Minister Pedro Sanchez presides over a weekly cabinet meeting with government ministers at the Moncloa Palace in Madrid, Spain, October 5, 2018. REUTERS/Sergio Perez

Riding high in the polls, Sanchez aims to serve a full term to mid-2020 as he focuses on approving next year’s budget and countering renewed independence moves in the Catalonia region.

But last week his science minister was forced to deny media reports he cheated on his taxes, days after a recording emerged of the justice minister using a homophobic slur.

Two other ministers have already been pushed out, one over a report she plagiarized her university degree, and a second over a 10-year-old tax fine. Both denied wrongdoing.

“This was not in the script,” a top party official said on condition of anonymity. “There is no consensus in the party on what we should do.”

The official and a second Socialist party source said some of its senior members, fearful the scandals are beginning to alienate voters, were lobbying Sanchez to go to the polls now to shore up his government while he still can.

The Socialists control fewer than a quarter of parliamentary seats but, according to a poll published last month, lead their nearest rivals - the conservative People’s Party (PP) - by around 10 percentage points.

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A snap election would add to political uncertainty in the European Union at a time when Britain is about to leave and populist parties across the continent campaigning for European Parliament elections are advocating a weakening of the bloc’s structures.

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Spanish elections would also be likely to reignite debate over Catalonia’s secession ambitions, a further potential headache for advocates of closer EU unity.

On the domestic front, the controversies over his cabinet team are particularly embarrassing for Sanchez, given he came to power on the back of a corruption scandal, ousting former PP leader Mariano Rajoy with a no-confidence motion in June.

The sources said the negative publicity could complicate Sanchez’s efforts to pass the 2019 budget, which Catalonia’s pro-independence leader would scupper if he made good on a threat to withdraw the support of national MPs aligned with him.

Sanchez, who has ruled out any moves towards independence by the wealthy northeast region, told Reuters in an interview last month that wrangling over Catalonia could cut short his administration.

The government has indicated that, to avoid a parliamentary standoff, it might abandon its own budget and stick to the one laid out by Rajoy, but analysts say any stalemate over finances could equally provide an excuse to call an election.

“Sanchez needs a reason to bring the election forward that distances him from the scandals about the ministers,” said Pablo Simon, a political science professor at Madrid’s Carlos III university.

If the September poll were translated into parliamentary seats, the Socialists, while still in a minority, would be in pole position to form a ruling coalition or another minority government.

But without a budget crisis to peg it on, bringing forward the vote could have a political cost.

“Calling elections is a sign of weakness,” said Narciso Michavila, director of polling firm GAD3.

If Sanchez keeps going to 2019, another big test awaits with municipal elections in May.