Austrians are electing a new Parliament, four months after a corruption scandal brought down ex-Chancellor Sebastian Kurz's coalition government with the far-right Freedom Party.
Some 6.4 million voters aged 16 and up are eligible to cast ballots for Sunday's election.
The Alpine country of 8.8 million has been run by a non-partisan interim administration appointed in June, after the publication of a video showing Freedom Party leader Heinz-Christian Strache appearing to offer favors to a purported Russian investor triggered the Kurz government's collapse.
Experts have predicted "whizz-kid" Kurz could once again partner up with the Freedom Party in a re-run of the coalition that has been touted by Hungarian Prime Minister Viktor Orban and other nationalists as a model for all of Europe.
But fresh allegations of wrong-doing have shaken the far-right over the past week.
Prosecutors confirmed Thursday they were investigating Heinz-Christian Strache, who resigned as FPOe leader and vice-chancellor in May because of "Ibiza-gate", over fraudulent party expense claims.
Kurz, whose center-right People's Party was leading recent opinion polls, will likely have to choose whether to form a fresh coalition with a chastened Freedom Party or team up with the center-left Social Democrats.
First exit polls will be released after voting ends at 5 p.m. (1500 GMT).
