An exit poll following Sunday's vote by broadcaster ORF showed Austria's Freedom Party leading with 29.1% compared to 26.2% for Chancellor Karl Nehammer's Austrian People's Party and 20.4% for the centre-left Social Democrats.
Herbert Kickl, head of the Freedom Party may struggle to put together a governing coalition.
Ahead of the vote, the Freedom Party was narrowly leading polls after a campaign focused on immigration, inflation and war in Ukraine. The Freedom Party leader has called European Commission chief Ursula von der Leyen a "warmonger" and opposes sanctions on Russia over its invasion of Ukraine.