The New South Wales Greens have passed a motion asking Upper House member Jeremy Buckingham to vacate his position on the party's ticket.
The State Delegates Council issued a statement saying the Greens would not be able to campaign effectively on urgent issues if he remained.
The development comes after Mr Buckingham was accused of sexual misconduct against a former party employee — an allegation he denies.
The council also committed to an independent review of the party, including looking into how it deals with harassment and bullying allegations.
Mr Buckingham said an independent investigation made no findings of wrongdoing.
"It's a sad and disappointing day for the NSW Greens," he said in a statement.
"While there are plenty of great people in the Greens and I have poured my heart and soul into the Greens for nearly 16 years, the fact is that the NSW Greens as an organisation is corrupt and rotten.
"Today the State Delegates Council of the NSW Greens abandoned grassroots democracy by overturning a democratic preselection result.
"They also threw justice under the bus by abandoning their own policies and due process to reward bullying behaviour and the lynch mob.
"This was a key test of principles for the NSW Greens and it has unfortunately failed that test."
