Left-leaning Alexander Van der Bellen's projected victory in Austria's presidential election is being welcomed across much of the political spectrum in Europe and neighbouring Germany.

Vice Chancellor Sigmar Gabriel, who heads Germany's centre-left Social Democrats, told the Bild newspaper, "A load has been taken off the mind of all of Europe."

He called the result "a clear victory for good sense against right-wing populism."

Manfred Weber, a conservative who heads the main centre-right group in the European Parliament, wrote on Twitter: "Austrians send clear pro-European signal. The European right-wing populists' party is off for now."

'Trump's election was the turning point'

Ulrich Kelber, a deputy German justice minister and Social Democrat, wrote: "Perhaps [Donald] Trump's election was the turning point. The liberal majority pushes back."

A leader of Germany's opposition Greens, Simone Peter, said it was "a good day for Austria and Europe. The right-wing rabble-rousers have to be stopped!"

APTOPIX Austria Presidential Election

Norbert Hofer, presidential candidate of the anti-migrant and anti-EU Freedom Party FPOe, and his wife Verena Hofer, left, attend the election party of his supporters in Vienna Sunday. Hofer conceded urged Austrians to 'stick together and to work together.' (Ronald Zak/Associated Press)

Austrian right-wing candidate Norbert Hofer conceded and said in a Facebook post that he is "endlessly sad" about his loss, adding, "I would have been happy to take care of our Austria."

Hofer conceded as preliminary results showed Van der Bellen ahead with 53.3 per cent of the vote compared to Hofer's 46.7 per cent. Those figures may change, but election officials say the margin is big enough to guarantee Van der Bellen's victory.

Hofer congratulated his rival and urged Austrians to "stick together and to work together." 

'Heavy defeat of nationalism'

Polls ahead of Sunday's vote had shown the two candidates neck-and-neck. The election is a court-ordered rerun of a May vote that Van der Bellen won by less than one percentage point.

The president of the European Parliament says left-leaning candidate Alexander Van der Bellen's victory in Austria marks a defeat for "anti-European, backward-looking populism."

Martin Schulz, who is a center-left Social Democrat from Germany, congratulated Van der Bellen on winning Austria's presidency "with a clear pro-European message and campaign."

Schulz added on Twitter that Van der Bellen's victory "is a heavy defeat of nationalism and anti-European, backward-looking populism."