Rebelo de Sousa’s share of the vote was put at between 49 and 55.7 percent, with his closest rival, independent leftist Antonio Sampaio da Novoa, said to have received between 19.3 and 25 percent.

Fifty percent is required to win in the first round. If no candidate reaches this threshold, a second round will be held on February 14.

Marisa Matias, the candidate for the Left Bloc, which is close to Greece’s anti-austerity party Syriza, was in third place, with between 8.8 and 12.4 percent of vote, according to the estimates.

Trailing in fourth was a Socialist former health minister, Maria de Belem Roseira, with between 2.9 and 5.9 percent of the vote, followed by Communist candidate Edgar Silva, with between 1.9 and five percent.

Portugal’s presidency has largely ceremonial duties, but has make-or-break power over the nation’s fragile ruling alliance and the right to dissolve parliament in the event of a crisis.

That authority means the ballot is being scrutinised in Europe, given the president’s potential impact on the country’s economic strategy.

Portugal is being watched by Brussels to see whether it will adhere closely to policies of economic stringency that unlocked a 78-billion-euro ($85-billion) bailout.

Elections were held in October but were inconclusive.

Since then, a minority Socialist government has been relying on a delicate coalition with the extreme-left to run the country of 10.4 million people.

It is having to count on the support in parliament of communists and greens critical of EU budgetary rules and Portugal’s membership of NATO.

Rebelo de Sousa, a former head of the centre-right Social Democratic Party, had been the clear favourite in the 10-candidate race.

Known to TV audiences as “professor Marcelo,” he came into the contest with a popularity built over decades in the public eye.

He has the backing of right wing parties but claims total independence, insisting he will not be partisan but seek to rule “above the fray”.

Prior to the election, he vowed to do “everything I can” to ensure the current government’s stability.

If his election is confirmed, he would succeed Anibal Cavaco Silva, a conservative who has served two consecutive five-year terms and who had been reluctant to hand power to a leftist coalition he viewed as “incoherent”.

The abstention rate in Sunday’s vote was between 48 and 53.2 percent, slightly lower than the record no-show of 53.5 percent in the last elections, in 2011.