APA quoted police saying the accident happened early Saturday morning in the south of the country when his car veered off the road near the city of Klagenfurt. He suffered severe injuries to his face and chest. It was not immediately clear if he died at the scene or in a hospital.
Haider was governor of Carinthia and leader of the far-right Alliance for the Future of Austria at the time of his death. He is survived by a wife and two daughters.
Haider, born in 1950 and active in politics since his teenage years, became a full-time politician in 1977 for the right-wing Freedom Party.
He caused an international backlash when the Freedom Party formed a coalition government with the conservative People's Party in 2000, triggering widespread condemnation and European Union sanctions.
After internecine struggles within the Freedom Party, Haider formed the breakaway Alliance for the Future of Austria in 2005. His new party only just scraped past the 4 percent threshold to enter parliament in a national election in 2006.
Over the summer, he staged a comeback in national politics and helped his Alliance for the Future of Austria significantly improve their standing in Sept. 28 national elections.
Media-savvy, he never stayed out of the limelight for long, offering to mediate hostage crises in North Africa with his good friend Seif al-Islam, the son of Libyan leader Moamer Kadhafi, and forcibly removing bilingual street signs in Carinthia, which has a strong Slovenian minority.
Haider also made headlines by campaigning on an anti-immigration ticket and with verbal gaffes.
He once reproached Austria's government by citing the "proper labour policies" of the Third Reich. On
Haider was also widely condemned for meeting Iraqi President Saddam Hussein in 2002, which he said was a "purely humanitarian" matter.
Born in Upper Austria, his father was a former member of Adolf Hitler's brown-shirted storm troopers. His mother was a teacher who had been a Hitler Youth leader.
AP and Reuters contributed to this report