Dutch anti-Islam politician Geert Wilders went on trial for alleged hate speech today, even as his popularity and influence in the Netherlands are near all-time highs.

Prosecutors say Wilders incited hatred against Muslims with remarks comparing Islam to Naziism and by calling for a ban on the Koran. Wilders argues that he has a right to freedom of speech and his remarks were within the bounds of the law.

If convicted, he faces up to a year in prison. He could keep his seat in parliament.

On his Twitter account, Wilders said the start of his trial was a "terrible day".

"The freedom of expression of at least 1.5 million people is standing trial together with me," he wrote, referring to the voters who made his Freedom Party the third-largest in national elections in June.

But his lawyer, Bram Moszkowicz, told presiding judge Jan Moors at the start of the trial that Wilders would not answer questions during the trial.

"My client will, at my advice, exercise his right to silence today, tomorrow and the other days," Mr Moszkowicz said. The judge then adjourned the case to consider a request from Wilders to explain his decision not to speak.

The far-right politician swept into the Amsterdam District Court complex in a police convoy and waved to supporters as he walked into the courtroom at the start of a trial scheduled to last seven days.

The case has generated huge interest in the Netherlands and the opening was broadcast live on television.

Wilders' party has agreed to support a new all-conservative government forming this month. In return, his political allies have promised to carry out much of his anti-immigration agenda.

Immigration-related issues have dominated politics in the Netherlands and much of Europe over the past decade. Wilders has drawn comparisons with populists such as Jorg Haider in Austria and Jean-Marie Le Pen in France as he cashed in on the growing unease and tested the limits of free speech.

Among more than 100 remarks his opponents see as offensive, an editorial in newspaper De Volkskrant stands out.

"I've had enough of Islam in the Netherlands; let not one more Muslim immigrate," he wrote in the paper. "I've had enough of the Koran in the Netherlands: Forbid that fascist book."

The flamboyant bleach-blond politician has also called for taxing clothing commonly worn by Muslims, such as headscarves - or "head rags," as he called them - because they "pollute" the Dutch landscape. He may be best known for the 2008 short film Fitna, which offended Muslims around the world by juxtaposing Koranic verses with images of terrorism by Islamic radicals.

However, his stances resound deeply with Dutch voters, who have reconsidered their famous tolerance amid fears their own culture is being eroded by immigrants who do not share their values.

The Wilders-supported government, expected to take power as early as this week, intends new measures to reduce acceptance of asylum-seekers and cut immigration from non-Western countries in half, notably by making it difficult for foreign spouses and children to join their Dutch citizen spouses.

It also plans to force immigrants to pay for their own mandatory citizenship classes.

A handful of anti-Wilders protesters gathered outside the court behind a banner reading "Fascism rules", with a Dutch pun on Wilders' name.

Convictions for discriminatory remarks are frequent in the Netherlands, but penalties are rarely greater than a small fine.

Prosecutors were initially reluctant to bring Wilders' case to court, saying his remarks appeared directed toward Islam as an ideology rather than intended to insult Muslims as a group.

But they were eventually ordered to do so by a judge.

Prosecutors will not rule out dropping charges or asking for no penalty at all when the trial comes to the sentencing phase. A verdict is expected on November 4.

Mohamed Rabbae, chairman of the moderate National Moroccan Council, said outside the court that he hoped judges would force Wilders to issue an apology for his past remarks.

"We are not for getting Mr Wilders in prison. We are for correcting him," he said.