Greens Senator Lidia Thorpe (Image: AAP/James Ross)

A prominent integrity advocate in federal Parliament has slammed Greens Senator Lidia Thorpe for failing to disclose a relationship with former bikie boss Dean Martin while she was on a law enforcement committee. 

Independent MP Helen Haines said Thorpe had made a “grave error of judgment” by not declaring the relationship and said the revelation proved why there should be a code of conduct for members of Parliament. 

“Senator Thorpe should have declared her relationship,” Haines told Crikey on Friday morning. 

Haines, the deputy chair of a select committee looking into the legislation for a proposed new integrity watchdog in Canberra, the National Anti-Corruption Commission (NACC), made the comments before heading into a public hearing on the matter. 

“Avoiding conflicts of interest and the appearance of conflicts of interest is vital for a member of Parliament,” the Indi MP said.

“This is why it is well overdue to introduce a code of conduct for all MPs, not just for ministers, so that such expectations are codified and followed by all.”

The NACC hearing on Friday will feature testimony from the Australian Public Service Commission, former heads of the NSW and ACT corruption watchdogs, and officials from the Department of the Attorney-General, among others. 

A separate select committee, looking into whether there should be a code of conduct for MPs, is due to deliver a report on the matter by December 1. 

The revelation Thorpe had been in an undisclosed relationship with Dean Martin, the former president of a Rebels motorcycle gang, prompted Greens Leader Adam Bandt to demand her resignation as the party’s deputy leader in the Senate. 

But Bandt is facing questions as well, including why his chief of staff didn’t tell him about Thorpe’s relationship despite being informed about it by her staff, according to the ABC, which revealed the affair on Thursday. 

Thorpe told the ABC she briefly dated the man in early 2021.

“We remain friends and have collaborated on our shared interests advocating for the rights of First Nations peoples,” she said.

It is not suggested that Thorpe shared any confidential information with unauthorised people, nor that Dean Martin, who has no criminal convictions, has any continuing association with outlaw motorcycle gangs.

Bandt said the failure of Thorpe to disclose the relationship to the party showed a “significant lapse in judgment”.

“Senator Thorpe says she understands this,” Bandt told reporters on Thursday afternoon.

“So I now expect her to demonstrate better judgment going forward and in exercising her continuing portfolio responsibilities.”

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