Pauline Hanson has made a controversial appearance on ABC's Q&A as police clashed with a handful of protesters who demonstrated for and against her on the street outside, arresting up to six people.

About 100 protesters began gathering at the ABC's headquarters in the Sydney suburb of Ultimo from 8pm on Monday night, ahead of the senator-elect's appearance on the live television show.

As Ms Hanson prepared to go to air, demonstrators - including Nick Folkes – the head of the Party For Freedom, who notably fought unsuccessfully in the Federal Court for the right to hold a rally commemorating the Cronulla Riots – stood holding signs including "welcome back Pauline" and "multiculturalism has utterly failed".

On the other side of the ABC's driveway, a tightly-packed group of counter-protesters held placards including "please explain" and "stand with Muslims against racism".

About 9.30pm, shortly before Hanson went to air, a small group of people wearing dark clothes and scarves on their faces appeared on the other side of Harris Street and were promptly tackled and arrested by police.

Police could not confirm how many people were arrested.

It is understood about half a dozen people were handcuffed and taken into police vans to move them away from the protest and no charges will be laid against them.

Inside the ABC studios, Ms Hanson clashed with her fellow panellists over combative questions that largely addressed Islam, and claimed her party has won up to seven seats in the Senate.

"We've got four and possibly up to seven seats that we could win," Ms Hanson said. "I have got to say thank you to Malcolm Turnbull for creating the double dissolution [election]."

Ms Hanson also addressed the controversy over television host Sonia Kruger, who suggested on Monday there should be a halt to Muslim migration to Australia. Ms Hanson threw her support behind the embattled presenter and called for a moratorium on the issue.

"You mentioned Sonia Kruger," Ms Hanson said to her fellow panellist, Labor senator Sam Dastyari. "I'm saying 'go Sonia' because I think it's great that someone actually is standing up."

Ms Hanson pumped her fist in the air as she cheered Ms Kruger on.

"She's expressed her feelings about it," Ms Hanson said. "She referred to Japan, for a population of 127 million people, they don't have terrorism on their streets.

"It is only in the last 10, 20 years that we have seen a rise of terrorism on the streets. You've got to ask yourself the question - why."

Ms Hanson said radicalisation was happening around the world, not just because she was "asking for a debate" around Islam.

"It's happening around the world because people, for whatever reason, are drawn to a religion or an ideology that is not compatible with the Western way of life and is having an impact on our culture and our way of life," she said.

"I'm concerned for every one of you here in this audience tonight and everyone at home because I want safety on our streets."