Australian Home Affairs Secretary Mike Pezzullo 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 on Friday (March 22) before a parliamentary committee one week after a terrorist murdered 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 one murder following the attack and was remanded without a plea.
He is due back in court on April 5, when police said he is likely to face more charges.
Mr Pezzullo was quoted as saying his department had "rededicated itself to standing resolutely against the extremist ideology of white supremacy and its adherence" in the wake of the attack.
"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 about the extent of white supremacy within Australia or what greater scrutiny threat would entail, ABC said.
He 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.
Mr Pezzullo was also questioned about reports that a man who helped to write a controversial speech for Senator Fraser Anning is also a Home Affairs Department employee, reported ABC.
Mr Pezzullo told senators he would investigate the matter but insisted 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 attack on Muslim immigration into New Zealand.
Australian Prime Minister Scott Morrison described the comments as "appalling" and "ugly" with "no place in Australia".
A teenager was widely praised for smashing an egg on Mr Anning's head in protest.
Meanwhile the Bangladesh government had issued a safety warning to its citizens travelling to Australia in the wake of Mr Anning's comments.