Irving, 67, has been in custody since his arrest in November on charges stemming from two speeches he gave in Austria in 1989 in which he was accused of denying the Nazis' extermination of 6 million Jews.
An eight-member jury and a panel of three judges will hear the proceedings, which officials said could produce a verdict within a day.
His trial opens amid fresh, and fierce, debate over freedom of expression in Europe, where the printing and reprinting of unflattering cartoons of the Prophet Muhammad has triggered violent protests worldwide.
Irving had tried to win his provisional release on euro 20,000 ($A32,370) bail, but a Vienna court refused, saying it considered him a flight risk.
His lawyer, Elmar Kresbach, said last month the controversial Third Reich historian was getting up to 300 pieces of fan mail a week from supporters around the world, and that while in detention he was writing his memoirs under the working title, Irving's War.
Irving was arrested on November 11 in the southern Austrian province of Styria on a warrant issued in 1989.
He was charged under a federal law that makes it a crime to publicly diminish, deny or justify the Holocaust.
Gas chambers
Within two weeks of his arrest, Irving asserted through his lawyer that he now acknowledges the existence of Nazi-era gas chambers.
In the past, however, he has claimed that Adolf Hitler knew little if anything about the Holocaust, and has been quoted as saying there was "not one shred of evidence" the Nazis carried out their "Final Solution" to exterminate the Jewish population on such a massive scale.
Vienna's national court, where the trial is being held, ordered the balcony gallery closed to prevent projectiles from being thrown down at the bench, the newspaper Die Presse reported.
It quoted officials as saying they were bracing for Irving's supporters to give him the Nazi salute or shout out pro-Hitler slogans during the trial, which will continue into Tuesday if a verdict is not forthcoming.
Irving is the author of nearly 30 books, including Hitler's War, which challenges the extent of the Holocaust, and has contended most of those who died at concentration camps such as Auschwitz succumbed to diseases such as typhus rather than execution.
In 2000, Irving sued American Holocaust scholar Deborah Lipstadt for libel in a British court, but lost. The presiding judge in that case, Charles Gray, wrote that Irving was "an active Holocaust denier ... anti-Semitic and racist".
Irving has had numerous run-ins with the law over the years.
In 1992, a judge in Germany fined him the equivalent of $US6,000 ($A8,128) for publicly insisting the Nazi gas chambers at Auschwitz were a hoax.