A high-powered parliamentary committee will investigate Lidia Thorpe's brief relationship with former Rebel bikies president Dean Martin after the Senate voted to refer the Green Party senator.
Thorpe also confirmed on Tuesday that he is still friends with Martin, with whom he had a relationship in 2021 when he was a member of the joint parliamentary law enforcement committee.
Greens leader Adam Bandt also revealed the Treasury was conducting a separate review of Thorpe's office and the Greens were reviewing their process after former staff complained about the way their complaints about senators were handled.
The Senate on Tuesday voted to refer Thorpe to the Senate privileges committee because he refuted suggestions that he had breached secrecy while he was on the committee and dating Martin.
Thorpe chose to refer himself to the committee and the Labor Party and Coalition backed the motion.
Prior to the Senate vote, Thorpe said he and Martin had met through "black activism and dated briefly".
"We remain friends and have collaborated in our common interests advocating for the rights of First Nations people," he said. “All confidential information I received as part of the joint law enforcement committee was treated confidentially.
"I strongly reject any suggestion that I will do anything other than comply with the terms of the committee and I have noticed that no one has offered any evidence to the Opposing side."
But Thorpe accepted that he "should have disclosed this relationship with Mr Martin to my leadership as well as the joint law enforcement committee of which I am a member".
“[But] I'm not going anywhere. Moreover, we do not have a treaty in this country, which I will continue to fight for," he said.
Addressing controversy in the House of Representatives Bandt said Thorpe had "advised me he remains friends with Mr Martin and his relationship with him begins in 2021".
“This means he was the Greens spokesman for justice and was also a member of the law enforcement joint committee at the time. Senator Thorpe has acknowledged that it should have been disclosed," he said.
Thorpe last week resigned from his position as deputy leader of the Greens in the Senate at Bandt's request after his relationship with Martin came to light.
Bandt confirmed that Thorpe's then chief of staff informed his chief of staff in 2021 about the relationship between the couple.
"He also told me that after subsequent conversations between the two chiefs of staff, my chief of staff understood that the matter had been addressed," Bandt said.
"He didn't tell me about the matter at the time, and I wasn't aware of the matter until the media brought it up."
Bandt said his chief of staff's failure to notify him meant he "did not live up to the expectations of the staff in my office on such matters" and he had advised the staff member.
"I also consider the primary responsibility to bring this matter to my attention sitting with Senator Thorpe and he has agreed that he should disclose this to me."
He told House Thorpe had assured him he had treated the committee's information confidential. Bandt said the Treasury was conducting a review of Thorpe's office and the Greens were also reviewing their process after former staff complained about the way their complaints about Thorpe were handled.
Shortly before the Senate vote, One Nation senator Malcolm Roberts said voters "need more" than committee referrals.
"He has established a pattern of behavior in this chamber that has no respect for the people, no respect for parliament and no respect for the Senate."