The Green Party will meet on 17 October to decide whether to remove Darleen Tana from Parliament.
At least three quarters of delegates will need to agree, for the party to decide to remove Tana using the waka-jumping law.
"This Special General Meeting will discuss the potential use of provisions in the Electoral Act, informally known as the party-hopping law, in the case of Darleen Tana," co-leader Chlöe Swarbrick said.
"Any use of this legislation will require consensus at that meeting, or at least 75 percent of support from those delegates. We will honour our grassroots members' decisions."
Tana had resigned from the party in July after an investigation found she likely knew of allegations against her husband's company, and had failed to tell the party.
She has remained as an independent MP.
The party had planned a meeting to decide whether to use the waka-jumping legislation to remove her from Parliament, but Tana took them to court - claiming the investigation went against the party's constitution and was unreasonable and unfair.
The High Court judgment on Friday rejected all Tana's claims.
Tana could still seek to appeal the decision, putting the meeting at risk of another rescheduling, but Swarbrick said the Greens were confident about moving forward with the meeting.
"Look, if I could tell you what Darleen Tana was doing, then we wouldn't have had to spend the last few months operating in the way that we have been."
Swarbrick repeated the party's position that Tana was not fit to be an MP.
She said there had been multiple times when Tana had not been present in the House, and had not assigned another party to deliver a proxy vote on her behalf.
"Which has meant that we have been votes-down on law."
Tana has, at times, selected Te Pāti Māori and the ACT Party to vote on her behalf.
She said party members were expected to raise any issues that may bring the party into disrepute and in this instance, the issues were not declared.
Tana was not available for comment.
