A terrorism expert has warned that Prime Minister Tony Abbott is feeding Islamic State's (IS) own propaganda machine by calling it a "death cult".

Abdul-Rehman Malik is the programs manager at Radical Middle Way, an outreach group for young Muslims.

"I think to call [Islamic State] a death cult, as the Australian Prime Minister does, is a complete misnomer and it actually feeds in to IS propaganda," he told the ABC's Lateline program.

"The propagandists of the Islamic State, when they hear themselves referred to as a death cult hell bent on global domination, are patting themselves on the back because you know what?

"You've bought in to their narrative."

Speaking at today's Countering Violent Extremism summit in Sydney, Mr Abbott said the threat posed by IS, also known as Daesh, was global.

"Daesh is coming, if it can, for every person and for every government with a simple message: 'Submit or die'," Mr Abbott said.

"The declaration of a caliphate, preposterous though it seems, is a brazen claim to universal dominion.

"You can't negotiate with an entity like this, you can only fight it."

Mr Malik, who attended the summit at the invitation of the Federal Government, said Mr Abbott was headed in the wrong direction.

Mr Malik said the demographic of young people joining Islamic State was the most unique in human history.

"Globalised, spiritualised, politicised. They come from backgrounds which are from all over the world," he said.

He said instead of taking away citizenship, the Government should be working with reformed extremists.

"It doesn't sound right... some of that language — the death cult language, the language of taking away citizenship is headed in the wrong direction," he said.

"There's going to be kids — it's already happening — who've gone out there, who've survived and who want to come back.

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"Don't take their citizenship away. They could be our best allies."

Daisy Khan, executive director of the American Society for Muslim Advancement, also attended the summit and told Lateline that the Muslim community was one of the most important stakeholders in the issue.

"There is an urgency in the community to really step up and take control of rooting out ISIS [Islamic State] and its messaging and its ideology," she said.

Mr Abbott today also said that Australia was discussing its military commitment in Iraq with coalition partners.

US president Barack Obama has approved the deployment of up to 450 additional American military personnel to train forces fighting Islamic State militants.

Australia currently has around 530 troops in Iraq.

Together with New Zealand soldiers, their role is a "behind the wire" on-base mission to train Iraqi army units.