NSW Greens MP Jeremy Buckingham claims party members were "bullied" into formally asking him to step down and insists he still enjoys widespread support.
The party's state delegate council on Saturday passed by a consensus a proposal to remove Mr Buckingham from the Greens' upper house ticket for the March 2019 election.
The motion said his presence would stop the party from campaigning effectively on urgent issues.
But Mr Buckingham said the decision was made "under duress" and "after a lot of pressure and bullying by other Greens MPs and factional opponents".
"I don't believe my party has lost confidence in me," he told ABC's Radio National on Monday.
"The vast majority of members have no say in these decisions."
He reiterated his view that the NSW Greens have been "infiltrated by an extreme left faction" whom he accused of using "toxic techniques" to get decisions they want.
"That includes online bullying, hectoring, really wearing people down, driving people away, and attacking any dissent with a really aggressive manner."
Mr Buckingham is refusing to budge and is considering legal options.
The MP has been the subject of a 2011 sexual harassment allegation re-aired under parliamentary privilege by factional rival Jenny Leong, although an independent investigation recommended no adverse findings against him.
He denies the alleged incident involving a party staffer and another claim by Ms Leong of intimidation.
NSW Greens MP Cate Faehrmann on Sunday threw her support behind Mr Buckingham.
In a post on Facebook, she claimed there had been a "hateful" campaign against Mr Buckingham whom she says has been subject to "bullying and attacks".
Australian Greens leader Richard Di Natale last month also called for Mr Buckingham to resign, saying the issue had gone on for "far too long".
Australian Associated Press