Austrians are casting their ballots Sunday in a first round of presidential elections that could play a role in blocking or advancing the country’s shift to the right.

An official report on Sunday in Vienna said the Social Democratic Party incumbent Heinz Fischer would retire in July after having served 12 years in office.

It said former Green Party leader Alexander der’Bellen, far-right Freedom Party legislator Norbert Hofer and the independent former Supreme Court Chief Irmgard Griss are top contenders to succeed Fischer.

The report stressed that they have scored between 22 per cent and 25 per cent each in recent surveys.

Although it is mostly a ceremonial role, the Austrian president also chooses the chancellor and swears in the cabinet after parliamentary elections.

In light of a possible victory for the opposition Freedom Party in the 2018 parliamentary elections, this year’s presidential vote may chart the course of Austrian politics.

The anti-immigration and anti-EU Freedom Party has enjoyed the support of 30 per cent of voters for nearly a year, coinciding with the surging migration crisis.

According to surveys, the social democrats and the centre-right conservatives that form the current government trail behind the rightists.

It said Van der Bellen promised that he would not appoint a Freedom Party-led government, as opposed to his right-wing rival Hofer.

The survey said neither of the three is likely to win a majority on Sunday.

It said the two candidates with the most ballots would therefore enter a run-off election in May.

The survey said the government parties’ candidates, social democrat Rudolf Hundstorfer and conservative Andreas Khol, stand very little chance of advancing into the next round.

Meanwhile, Griss has said she would respect the election outcome and would appoint such a cabinet. (dpa/NAN)