CANBERRA • Australian Home Affairs Secretary Mike Pezzullo has warned white supremacists living in the country that they are on the "radar" of the authorities, and will face more scrutiny and pressure in the wake of the deadly Christchurch shootings.

The senior official made the comments yesterday before a parliamentary committee one week after a terrorist massacred 50 Muslims worshipping at mosques in neighbouring New Zealand, Australian broadcaster ABC reported.

Australian Brenton Tarrant, 28, a suspected white supremacist, has been charged with murder following the attacks, and is likely to face more charges.

Mr Pezzullo was quoted as saying that his department had "re-dedicated itself to standing resolutely against the extremist ideology of white supremacy and its adherence" in the wake of the attacks.

"You are on our radar and you will not be able to incite the racial strife that you seek," he said, according to ABC.

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

Mr Pezzullo did not elaborate on the extent of white supremacy within Australia or what the greater scrutiny threat would entail, ABC reported.

The official described the massacre as a "horrific slaughter of Muslims at prayer".

"The department has since been working ceaselessly with our colleagues in ASIO (Australian Security Intelligence Organisation), the AFP (Australian Federal Police) and other agencies to assist our New Zealand comrades with the investigation into this unspeakable act and with other elements of the New Zealand government's response," Mr Pezzullo said.

He was also questioned about reports that a man who helped to write a controversial speech for Senator Fraser Anning is a Home Affairs Department employee, reported ABC.

Mr Pezzullo told senators that he would investigate the matter, but insisted that those with extremist views were not welcome in his department.

"Any association with groups that vilify minorities, that either normalise or incentivise violence, is completely abhorrent," he said.

Mr Anning, a far-right lawmaker, has been widely condemned in recent days for blaming the Christchurch attacks on Muslim immigration into New Zealand.

Australian Prime Minister Scott Morrison described the comments as "appalling" and "ugly", and having "no place in Australia".

A teenager was widely praised for smashing an egg on Mr Anning's head in protest.