The Somali-born Dutch MP who describes herself as a "dissident of Islam" has backed the Danish newspaper that first printed the Prophet Muhammad cartoons.
Ms Hirsi Ali compared Islamism to communism
Ayaan Hirsi Ali said it was "correct to publish the cartoons" in Jyllands Posten and "right to republish them".
Her film-maker colleague Theo van Gogh was murdered by a Muslim extremist in a case that shocked the Netherlands.
Ms Hirsi Ali, speaking in Berlin, said that "today the open society is challenged by Islamism".
She added: "Within Islam exists a hardline Islamist movement that rejects democratic freedoms and wants to destroy them."
Ms Hirsi Ali criticised European leaders for not standing by Denmark and urged politicians to stop appeasing fundamentalists.
She also said that although the Prophet Muhammad did a lot of good things, his decree that homosexuals and apostates should be killed was incompatible with democracy.
Ms Hirsi Ali wrote the script for Submission, a film criticising the treatment of women in Islam that prompted a radical Islamist to kill Van Gogh in an Amsterdam street in November 2004.
Papers in several European nations have reprinted the satirical Danish cartoons - most recently carried in the French magazine Charlie Hebdo.
A dozen people have died in violent protests in Afghanistan over the cartoons, which have also been denounced throughout the Islamic world.
The drawings include an image of Muhammad with a bomb in his turban. Islamic tradition explicitly prohibits any depiction of Allah and the Prophet.
Ms Hirsi Ali said the furore over the cartoons had exposed the fear among artists and journalists in Europe to "analyse or criticise intolerant aspects of Islam".