Senator Lidia Thorpe has resigned as deputy leader of the Greens in the Senate over what leader Adam Bandt called a “significant lack of judgment”

On Thursday the ABC revealed Thorpe had confirmed she “briefly dated” Dean Martin in 2021 and remains friends with him.

Thorpe accepted she had “made mistakes and … not exercised good judgment” over a failure to declare the relationship with the former president of the Rebels bikie gang.

The relationship reportedly sparked staff concerns about a possible perceived conflict of interest with her duties on the joint parliamentary law enforcement committee.

Guardian Australia does not suggest that Thorpe shared any confidential information with any person not authorised to receive it.

Bandt said that “at a minimum” Thorpe needed to declare her relationship with Martin and in failing to do so she showed “a significant lack of judgment”.

Bandt noted that Thorpe had not held the justice portfolio since the election, but said she still had “important work to do on First Nations justice including on progressing Truth, Treaty and Voice”.

“I accept that I have made mistakes and have not exercised good judgment. “I will now reflect on this and focus on my important portfolio work, especially advocating for First Nations people.”