Austria's far-right candidate in the October presidential election is "playing with fire" with talk of an EU membership referendum, his challenger told media on Friday, vowing to tackle him over the issue during the campaign. If the Freedom Party (FPOe) and Norbert Hofer "are going to fantasize about an EU exit, they are playing with fire," Alexander Van der Bellen, 72, told the Oesterreich daily. The far-right "has been flirting for years with leaving the EU and the euro zone... I am going to make it an issue (in the campaign), of course, whether Hofer and the FPOe like it or not." Hofer, 45, and the anti-immigration FPOe appeared to toughen their stance on Austria's membership of the European Union in the wake of Britain's June 23 vote to leave the bloc. "If the EU develops in the wrong way, instead of returning to its actual basic values, if it becomes more centralized, and if Turkey joins, then for me it would be time to say that Austrians must also be asked (about membership)," Hofer said after the "Brexit" vote. But in an interview with daily Die Presse to be published on Saturday, while sticking to his call for a referendum if any of those "extreme" things happened, Hofer insisted he was not in favour of an Austrian "Oexit." "I don't want Austria to leave the EU. Because that would be a mistake," the paper quoted him as saying. "Leaving the EU would be the last resort, if Turkey joins the EU or there are new centralist treaties." In the past, he has said that if Austria weren't already a member of the EU, he would oppose joining, calling for a "Europe of fatherlands." A poll published by Oesterreich on Friday, albeit of only 600 people, found 52 percent of those surveyed were against Austria leaving the EU, 30 percent in favor and 18 percent undecided. Sixty percent opposed a referendum. Van der Bellen, an independent backed by the opposition Greens — candidates from the governing centrist parties were knocked out in the first round — beat Hofer in a May 22 run-off but by only 30,000 votes. A far-right legal challenge succeeded in getting a court to annul the result on July 1 because of widespread procedural errors. A new election, expected to be equally knife-edge, is on Oct. 2. Traditionally the Austrian head of state's job has been largely ceremonial but Hofer has set alarm bells ringing by suggesting he would make use of hitherto untapped powers afforded under the constitution. Hofer becoming the EU's first far-right president would also be of enormous symbolic importance for the FPOe two years before the next scheduled general election, and be a fillip to other populist parties in Europe. Van der Bellen's comments came on the day he was meant to be sworn in if his May victory had not been declared null and void, with incumbent Heinz Fischer formally stepping down in a ceremony on Friday. Fischer has been replaced on an interim basis by the speaker of parliament Doris Bures and her two deputies, one of whom is Hofer. He has rejected calls to step down from this post during the campaign.