Austrians are voting in a re-run of a presidential election which pits the leader of the far-right Freedom Party Norbert Hofer against former Green Party head Alexander Van der Bellen, BBC reports.

The vote last May was narrowly won by Mr Van der Bellen, but the result was overturned by Austria's highest court because of irregularities in the count.

If Mr Hofer wins, he will become the EU's first far-right head of state.

Opinion polls held in November suggest the vote is too close to call.

Although the role is largely ceremonial, the vote is being watched as a barometer of how well populist candidates will do in upcoming elections.

France, the Netherlands and Germany all face elections next year in which anti-mainstream and anti-immigration parties are gaining ground.

The direction in which Austria will take with regard to the EU is also closely watched.