The New South Wales Greens upper house MP Jeremy Buckingham has successfully shut down a complaint backed by Senator Lee Rhiannon to oust him from the party for criticising her on the ABC’s Four Corners.

Buckingham threatened to take legal action against the party if it proceeded to hear the complaint, on the grounds that it was procedurally unfair.

The threat of legal action has persuaded the conflict resolution committee – a randomly selected group of four office-holders – to fold and recommend mediation of the complaint instead.

Despite that concession, further factional battles are brewing. Cate Faehrmann is challenging an attempt to prevent her from replacing Mehreen Faruqi in the NSW upper house and there is pressure on Rhiannon to step aside for Faruqi, who beat her in a preselection battle in November.

Faehrmann, a former NSW upper house MP and chief of staff to the federal leader, Richard Di Natale, has transferred her membership from the Victorian branch back to NSW but only been given “provisional” status.

The three-month provisional status would prevent her nominating to fill Faruqi’s vacancy by the 10 April deadline.

She has provided the NSW Greens with legal advice that transferring members are entitled to full membership, and will consider a court challenge if her bid is rejected.

Greens factional tensions in NSW erupted when the complaint against Buckingham was revealed on Wednesday.

The complaint, signed by eight Greens members and containing testimony from Rhiannon and her partner, Geoff Ash, accuses Buckingham of “serious and false criticisms” for suggesting in a Four Corners episode in August that Rhiannon thwarts democratic reform.

On Thursday the NSW Greens co-convenor Debbie Gibson informed members that she and the complaints committee had decided to “suspend the complaints process and disband” after receiving a letter from Buckingham’s lawyers.

The group recommended that the Greens seek legal advice about its complaints process because the letter argued the process was procedurally unfair and would not withstand a legal challenge. They urged the parties to undertake mediation.

In a statement on Facebook, Buckingham welcomed the “good news” that the push to expel him had been suspended and the complaint committee disbanded.

“While the Greens need a robust and fair complaints process, we must ensure that it cannot be misused to try and punish those who hold and express differing political views,” he said.

“As a grassroots party with a founding principle of peace and non-violence, political differences within the Greens should be respected, discussed openly and ultimately decided democratically by members.”



Linda Eisler, a Green on Canterbury council and one of the complainants, told Guardian Australia that she is “not giving up trying to expose the truth” and would consider options such as raising the Buckingham complaint at state delegates’ council on the weekend or relodging the complaint.

The suspension of the complaint is a victory for Buckingham, who faces preselection in April and May this year for the 2019 state election, along with fellow upper house member David Shoebridge.

The Greens’ affirmative action rules require a woman to hold one of the top two spots, meaning that Shoebridge could be relegated to the winnable, but difficult, third spot if he loses to Buckingham.

Factional opponents of Rhiannon have suggested she may attempt to swap to the NSW upper house by now nominating for the vacancy or the ticket.

“I’m not running in any preselection,” Rhiannon told Guardian Australia. “[This] is not going to change ... it was never on the cards.”

Since Faruqi defeated Rhiannon in a preselection contest in November, some Greens members have put pressure on Rhiannon to quit the federal Senate, allowing Faruqi to fill the vacancy and contest the next half-Senate election as an incumbent.

In Queensland, Senator Andrew Bartlett has announced he will run for the seat of Brisbane rather than contest preselection against the former senator Larissa Waters and challenger Ben Pennings.

When he announced the move in February, Bartlett said he would stay on in the Senate “throughout this year”.

The senator’s position would help him maintain his profile in the lead-up to the election but Bartlett is likely to face similar pressure to stand down to allow Waters or Pennings to have the benefits of incumbency in the Senate election.