Activist and author Ayaan Hirsi Ali has canceled an upcoming trip to Australia and New Zealand over security concerns, organizers have confirmed. A well-known critic of conservative Islam's treatment of women and homosexuality, Ali lives with round-the-clock protection due to the number of death threats she has received.

Think Inc, the organizers of Ali's "Hero of Heresy" tour, wrote on Twitter that it "regrets that, for a number of reasons including security concerns, Ayaan Hirsi Ali must cancel her upcoming appearances in Melbourne, Brisbane, Sydney and Auckland."

Hirsi Ali had been due to appear on Australia's Q & A panel show, as well as give several speaking engagements. A spokeswoman for Think Inc told Guardian Australia that they were "incredibly disappointed" that the controversial activist was forced to stay away.

Her critics, however, rejoiced at the news on social media. An online petition posted by a member of the public on the change.org platform accused Hirsi Ali of spreading "hostility and hatred towards Muslims," and a well-circulated video featuring several Muslim Australian women said Ali used the "language of white supremacy" to criticize their religion.

Born in Somalia in 1969, Hirsi Ali fled to the Netherlands in 1992. She worked in refugee centers and hostels for abused women as a Somali-Dutch interpreter while working towards her masters degree at Leiden University. She has said that her experiences in Somalia, as well as the September 11 attacks influenced her disenchantment with Islam.

Ali: violence 'inherent' to Islam

The writer has compared Islam to Nazism, said that "violence is inherent" to its practices, and has called the Prophet Muhammad a "pervert and a tyrant." In 2002, she collaborated with ardent anti-Islam filmmaker Theo van Gogh to make a short film about the oppression of Muslim women. Both received death threats, and van Gogh was assassinated months later.

She was elected to Dutch parliament in 2003, but was forced to resign in 2006 after an investigative television program revealed she had lied about her name, age and country of residence on her Dutch asylum application. They also cast doubt on her claims that she had fled an arranged marriage, citing witness testimony that she had met her ex-husband before the wedding and approved of the ceremony. Later that year, following a government crisis over her status, she relocated to the US.

Recipient of numerous awards for free speech and support of worldwide democracy,  Hirsi Ali's most recent book "Heretic," published in 2015, is considered to be a "mellowed" version of her fiery rhetoric. According to the New York Review of Books, the work excoriates radical Islam and the Western liberals who label her an Islamaphobe, but supports reform efforts by moderate Muslims.

At least 2,000 tickets had been sold for Hirsi Ali's engagements in Australia and New Zealand. Think Inc said she "hopes to be able to return…in the not-too-distant future."