Home Affairs boss Michael Pezzullo said the department joined global expressions of shock and grief at the horrific slaughter of 50 Muslims at mosques in New Zealand a week ago.

"The department has rededicated itself to standing resolutely against the extremist ideology of white supremacy and its adherents to whom I say: 'You are on our radar and you will not be able to incite the racial strife that you seek'," Mr Pezzullo told a Senate estimates hearing in Canberra on Friday.

"The scrutiny and pressure you are under will only intensify."

Australian white supremacist Brenton Tarrant, 28, has been charged with murder after the shootings which left dozens more injured.

Mr Pezzullo said Australian authorities were working with their New Zealand "comrades" on the investigation and response to the terror attacks.

Australian Associated Press