Conservative law professor and journalist Marcelo Rebelo de Sousa has won Portugal's presidential election, gaining a majority of the vote in the first round.
Rebelo de Sousa had 52 per cent of the votes cast with 99 per cent of ballots counted, the country's election commission said.
The outcome means Rebelo, 67, will avoid a run-off scheduled to take place on February 14.
Earlier projections put Antonio Sampaio da Novoa, the socialist-oriented long-time rector of the University of Lisbon, in second with between 22 and 25 per cent of the vote.
After serving two terms in office, current President Anibal Cavaco Silva is obliged to step down on March 9.
The president in Portugal has the power to veto legislation, dissolve parliament and call new elections.
Portugal's economy returned to growth in 2014, three years after receiving a 78-billion-euro ($A120.28 billion) bailout program from the European Union and the International Monetary Fund.
Although Rebelo de Sousa belongs to the liberal opposition Social Democratic Party, he assured voters repeatedly that he would support the government of socialist Prime Minister Antonio Costa.
But he also warned that the planned softening of a reform and austerity program should not occur at the expense of budget discipline.
