Attacks on centres for asylum seekers in Austria are on course to double this year, according to government figures released on Saturday.

Twenty-four were recorded in the first half of 2016, compared with 25 for the whole of 2015, Interior Minister Wolfgang Sobotka said in reply to a parliamentary enquiry.

The incidents ranged from arson to acid attacks to stones thrown through windows, or racist or Nazi graffiti and hate postings on the Internet.

Opposition Green MP Albert Steinhauser, who made the enquiry, blamed the rise on the "heated political debate about asylum seekers."

"If in politics there is an atmosphere of intolerance... then it's no wonder that some people see such attacks as legitimate," Steinhauser said.

Austria saw a record 90,000 people apply for asylum last year, one of the highest levels per capita in Europe.

The far-right Freedom Party (FPOe), in common with similar parties across Europe, has stoked concerns about the influx to boost its support.

Polls put the FPOe's Norbert Hofer neck-and-neck with independent ecologist Alexander Van der Bellen to be elected to the largely but not entirely ceremonial post of president on December 4.

A victory for Hofer would make him Europe's first elected far-right head of state since 1945.