Seven of the 56 people investigated over several foiled terrorist attacks on home soil came to Australia as refugees, the country's head of intelligence says.

All of them - bar one - migrated as young children with their parents.

ASIO director-general Duncan Lewis was armed with the figures as he fronted a parliamentary committee for the second time this year.

In May, Mr Lewis was quizzed by One Nation leader Pauline Hanson about the number of refugees or children of refugees involved in disrupted attacks.

At the time, he said he had no evidence to suggest there was any connection between refugees and terrorism.

In his opening statement on Tuesday, he noted there had been 13 major plot disruptions since September 2014.

Of the 56 people who were either arrested, charged or the subject of search warrants during those operations, only seven came to Australia as refugees.

Six of those were aged 11 or younger when they migrated with their parents.

"Where an individual is involved in attack planning and arrived as a refugee, they generally arrived as a child and have spent more time in Australia than they have elsewhere," Mr Lewis said.

"Stereotyping any group as a source of threat is not helpful. It is behaviour, not background, which ASIO is investigating."

Mr Lewis said his agency's investigations focused only on a small number of Australians who are committed to anti-Western, violent, Sunni Islamist extremist ideology - many of whom were born here.

He reiterated that more than 99.99 per cent of Australian Muslims are of "no security interest" to ASIO.

"Traits such as ethnicity do not necessarily help us to identify the individuals who are of concern," he said.

The threat of terrorism in Australia and to Australian interests continued to be shaped by Islamic State and the conflict in Syria and Iraq, Mr Lewis said.

While IS had undergone serious setbacks, losing its strongholds in Mosul, Raqqa and Marawi, it had not eliminated the threat.

"ISIL propaganda remains a powerful force for radicalisation and incitement and the threat from ISIL-inspired lone actors and local groups will endure," he said.

The number of Australian foreign fighters in the Middle East remains at around 110.

At least 68 Australians have been killed in Syria or Iraq, but that number could be as high as 85.