Former Australian Prime Minister Tony Abbott has sparked criticism by saying Islam has a "massive problem" and needs to reform.

Writing in Australian media, Abbott said "not all cultures are equal" and the West should stop apologising for defending its values.

Opposition leader Bill Shorten said the comments were "counterproductive".

Current Prime Minister Malcolm Turnbull said the vast majority of Muslims were "appalled" by extremism.

Speaking to reporters in Perth, Turnbull said it was "absolutely vital to ensure that we don't make the mistake, which is what the terrorists want us to do, of tagging every single Muslim with the responsibility for the crimes of the few".

While it was "no revelation" that there were violent elements in the Muslim world, the religion is compatible with democracy and an open society, he said, and most victims of extremist groups are Muslims.

Turnbull would not comment on his predecessor's remarks directly, but advised that his own statements on extremism were always "carefully calculated" to "make Australia safer and to make the work of our security services less difficult than it already is".

'Not culturally insensitive'

Abbott was removed as prime minister by a party vote in September amid poor poll ratings and is now a backbench MP. Before his political career he had trained to be a Catholic priest.

His letter, published in News Corps tabloids, cautioned against "demonising" Muslims, but said the West "can't remain in denial about the massive problem within Islam".

"Although most Muslims utterly reject terrorism, some are all too ready to justify 'death to the infidel'," he said.

"Islam never had its own version of the Reformation and the Enlightenment or a consequent acceptance of pluralism and the separation of church and state.

"It's not culturally insensitive to demand loyalty to Australia and respect for Western civilisation. Cultures are not all equal.

"We should be ready to proclaim the clear superiority of our culture to one that justifies killing people in the name of God."

He also said only Muslims could tackle supporters of violent extremism, and that "everyone interested in a safer world should be reaching out to 'live and let live' Muslims and encouraging them to reclaim their faith from the zealots".

Nail Aykan, executive director of Islamic Council Victoria, told the BBC Abbott's comments were "completely unhelpful at a time when we are trying to foster unity and social cohesion in Australian society".

He advised Abbott to "go out and meet some real local Muslims and get their perspective before you start patronising a whole population".

Bill Shorten of the opposition Labor party said that "making assertions about cultural and religious superiority is entirely counter-productive".

"Inflammatory language undermines efforts to build social cohesion, mutual respect and has the potential to harm the efforts of national security agencies to keep Australians safe," he said, saying Turnbull should "pull Tony Abbott into line".

Greens leader Richard Di Natale told Sky News Abbott was "an incredibly divisive, destructive force" in Australian politics, while Labor MP Ed Husic - who is a Muslim - said he was begging MPs "to think carefully about what they are saying".

Australia is involved in the US-led international military operation against Islamic State militants in Iraq and Syria, and is increasingly concerned about Australians fighting with or supporting the militants.

Several raids have been carried out and officials say a number of plots have been disrupted. Last month, a teenage boy who police say had been radicalised shot dead a police worker in Sydney.