The federal government is looking at suspending the citizenship privileges of sole Australian nationals fighting with terrorist groups, as the prime minister, Tony Abbott, says the Islamic State group is “coming after us”.

But Abbott says there will not be any immediate tightening of security in Australia after three terrorist attacks overseas.

The immigration minister, Peter Dutton, says the government is considering options relating to the citizenship of 60 Australian nationals fighting in the Middle East, but declined to provide more details.

“We want to make sure that we can protect the Australian people as best we can and if people have committed a criminal offence they will face the full force of the Australian criminal law,” he told reporters in Melbourne on Saturday.

He would not say what rights could be suspended.

Australia will block the return of dual citizens suspected of terrorism, based on security advice, and deport court-convicted terrorists under new national security laws.

It is also looking at making the laws retrospective, meaning terrorists in jail could be deported after serving their sentence, but Dutton said he did not have an update on this from the government’s citizenship committee.

He said the committee had held an initial meeting to explore the big picture and other issues would follow.

Dutton said there had been two terrorist attacks in Australia since September last year.

Six attacks had been thwarted, he said, and the Australian Security Intelligence Organisation was investigating 400 high-priority matters.

“We need to take this threat of terrorism very, very seriously,” he said.



Tony Abbott says Isis is at war with Australia and ‘it’s coming after us’. Link to video

The prime minister says it is important to remain vigilant and that everything is being done to destroy Daesh (Islamic State) at home and abroad.

“This illustrates yet again that as far as the Daesh death cult is concerned, it’s coming after us,” Abbott said.

“We may not always feel that we are at war with them, but they certainly think that they are at war with us.”

Abbott said about half of the Australians who have gone abroad to fight with IS are sole nationals.

“The legislation that is before the parliament now obviously gives us a way of saying to dual nationals ‘you’re never coming back’.

“We need ways of dealing with those who are not dual nationals.

“Just as going abroad to fight with the death cult is the modern form of treason, perhaps to deal with it [we] need the modern form of banishment.”