Opposition Leader Peter Dutton says he believes Greens Senator Lidia Thorpe is "not fit" to serve in the federal parliament after she admitted to briefly dating an ex-bikie while sitting on a law enforcement committee.
Senator Thorpe resigned her leadership position within the Greens on Thursday after the ABC revealed she had a relationship with the former president of the Victorian Rebels, Dean Martin, while also holding a role on a parliamentary committee which received confidential police briefings about organised crime.
Mr Dutton said the matter was a "test of leadership" for Greens leader Adam Bandt and called on him to expel Senator Thorpe from the party.
"I've never seen anything like this in my 20 years in parliament. It's clear that Senator Thorpe is not fit to be in the Australian Parliament," Mr Dutton said.
"Adam Bandt needs to step up to show leadership and to kick Lidia Thorpe out of the Greens and to kick her out of the parliament, because she has no place in the parliament with this sort of conduct."
Senator Thorpe on Thursday resigned as the Greens' deputy leader in the Senate while conceding she had "made mistakes" and had "not exercised good judgement".
Mr Bandt said Senator Thorpe showed a "significant lack of judgement" for failing to disclose her connection to Mr Martin.
"It was clear that this could be perceived as affecting her work and her failure to disclose that, at the very least, to me was an error of judgement," Mr Bandt said.
"It is disappointing because it is an error, a significant error of judgement from someone who has a lot to offer this country and a lot to offer this parliament."
While Mr Bandt requested Senator Thorpe resign from the party's leadership team, he said he continued to have confidence in her as a senator.
"Senator Thorpe is a fighter for her people and has strong and passionate views about advancing justice for First Nations people," he said.
"She has the potential to be a very good senator, fighting for her people and fighting for justice, but she will need to show better judgement to do that."
Senator Thorpe has insisted committee documents were "treated in confidence" and the ABC does not suggest she shared confidential information with anyone unauthorised to received it, nor does the ABC suggest Mr Martin has any continuing association with outlaw motorcycle gangs.
Prime Minister Anthony Albanese described the revelations as "astonishing" and said it was "appropriate" that she had been forced to relinquish her leadership role.
However, he questioned the Greens' handling of the undisclosed relationship.
"I find it astonishing that it was reported by her staff to Adam Bandt's office, and he apparently wasn't told," Mr Albanese said.
"That raises issues of the functioning of that office."
While Senator Thorpe's staff raised the matter with Mr Bandt's office a year ago, Mr Bandt said he had no knowledge of the relationship until contacted by the ABC.
"I expect that I should have been told about this, and I have made that clear to my chief of staff, and I have counselled him," Mr Bandt said.
