The Department of Home Affairs head, Mike Pezzullo, has said his staff are zeroing in on white supremacists and their sympathisers in the week following the Christchurch terror attack, including, if necessary, those within his own department.

Pezzullo’s comments on white supremacy come just a week after he delivered a speech to the Australian Strategic Policy Institute where he listed “seven gathering storms” for national security, where “radical extremist Islamist terrorism” was mentioned, but white supremacy was not.

But speaking to a Senate estimates hearing on Friday, Pezzullo said the department had “rededicated itself to standing resolutely against the extremist ideology of white supremacy and its followers.

“To whom I say, you are on our radar and you will not be able to incite the racial strife that you seek,” he said. “The scrutiny and pressure that you are under will only intensify.”

Responding to reports in the Sydney Morning Herald and the Age that one of Fraser Anning’s staffers, accused by Pauline Hanson in parliament of having written the infamous “final solution” speech, was on unpaid leave from his department, Pezzullo said he would investigate.

Hanson used parliamentary privilege to name Richard Howard as the author of Anning’s maiden speech, a claim Howard has denied. Howard has also rejected allegations he holds extremist views.

“Richard Howard actually did work in Senator Malcolm Roberts’s office and was sacked out of that office,” Hanson told the Senate the day after Anning’s speech.

“He did ask me for a position in my office, after Senator Roberts lost his position in this parliament, and I refused to take him on.”

Howard told the Nine newspapers he had “no position” on Anning’s views and his job was to deal with constituent inquiries.

But Pezzullo said he would examine all claims, telling the hearing his department “will not tolerate extremists of any description – any form of extremism is repugnant”.

“Any association with groups that vilify minorities that either normalise or incentivised violence is completely abhorrent,” he said.

“You will not be working in my department if you hold those views.”

While political staffers can claim privilege, Pezzullo said that was extended both ways.

“If it is the case that I can’t look into a matter that is being undertaken in a privilege fashion, that is to say a member of staff working for a senator, I will do everything within my power to look at ancillary associations that I can look into,” he said.

“Privilege cuts both ways, it has to be said, and if it comes to be the case whether in this, or any other matter, I am not going to speculate, but I will set the standard – no one will work in my department, who holds those views, I can assure you.”