One Nation leader Pauline Hanson has been urged to sack her most senior parliamentary colleague over historical posts boosting conspiracy theories and anti-Semitic tropes.
While Senator Hanson has been in Europe, meeting with far-right activist Tommy Robinson in the UK and lounging poolside with billionaire donor Gina Rinehart in Italy, Malcolm Roberts has been embroiled in controversy over his resurfaced comments.
In an appearance on The Alex Jones Show in 2024, Senator Roberts praised the notorious American conspiracy theorist, who spread claims the Sandy Hook massacre was staged by the US government as a pretence for stricter gun control and the September 11 terrorist attacks were an inside job.
The controversial Queensland senator, who was elected in 2016, took to social media to defend his past comments.
"First they came for Pauline. Then they came for Barnaby. Now it's my turn," Senator Roberts wrote on X on Thursday.
"Selective cherry picking and dishonest distortions by mainstream media to mislead Australians on behalf of their 'uniparty' mates."
First they came for Pauline.
— Malcolm Roberts 🇦🇺 (@MRobertsQLD) July 16, 2026
Then they came for Barnaby.
Now it's my turn.
Selective cherry picking and dishonest distortions by mainstream media to mislead Australians on behalf of their uniparty mates. https://t.co/FBo4sLq36m
One Nation MP Barnaby Joyce earlier distanced himself from his colleague's actions.
"Sandy Hook was an outrageous murder of innocent people," he told ABC Radio on Thursday."
"It was no false flag event. Neither was 9/11."
Senator Roberts has entertained a similar claim the Bondi terror attack, in which two gunmen targeted Hanukkah celebrations, was also a "false flag".
As One Nation's rise in the polls means it courts a more mainstream demographic, the party's associations with figures such as Jones and Robinson are coming under greater scrutiny.
Mr Joyce was also asked about a social media post Senator Roberts shared in 2024 of a mural that repeated an anti-Semitic trope about Jews controlling global finance and politics.
"For too long people have been blind to the Uniparty with Liberal and Labor pushing the same globalist UN-WEF policies," Senator Roberts wrote in the caption.
But Mr Joyce declined to be drawn in.
"I'm not here to start carpeting Malcolm," he said.
Independent MP Allegra Spender said One Nation leader Pauline Hanson should demand Senator Roberts' resignation.
"It's shameful that one of One Nation's most senior MPs should endorse and share this notorious anti-Semitic slur," she wrote.
One Nation Senator Malcolm Roberts should resign. Pauline Hanson should demand his resignation.
— Allegra Spender (@spenderallegra) July 16, 2026
It's shameful that one of One Nation's most senior MPs should endorse and share this notorious Antisemitic slur.
Will Pauline Hanson or Barnaby Joyce ever hold him to account? pic.twitter.com/2RayXbmbyW
Media also resurfaced a 2025 interview Senator Roberts conducted with vaccine sceptic and former pilot Graham Hood.
In the video, the pair downplay the widespread chemtrails conspiracy theory, although Senator Roberts says it is likely the US military is "doing trials on these things".
Senator Roberts' previous praise for Vladimir Putin added to a long list of questions for Senator Hanson about her colleague, Opposition Leader Angus Taylor said.
"And the question here for Pauline Hanson is what is she going to do about it?" he said.
"She's over in Italy living it up it seems. She needs to deal with this ... now."
While Mr Joyce would not back Senator Roberts, he defended Senator Hanson's meeting with Robinson earlier in July.
The UK activist, whose real name is Stephen Christopher Yaxley-Lennon, has advocated for people to "make war" on Islam and has been convicted of assault on more than one occasion.
"I don't support so much what Tommy Robinson does, but I think it's incredibly important that we understand the social dynamic and how that came about," Mr Joyce said.