A Greens member complained to the party's preselection disputes committee (PDC) about an email in which Mr Buckingham encouraged members to participate in voting, linking to the videos posted by the candidates on their Facebook pages.

Federal and state MPs are prohibited from making comments on preselections or communicating with members using party-privileged membership databases on preselection matters.

The PDC upheld the complaint but recommended that no further action be taken.

The finding comes amid continuing acrimony over the preselection of Northern Rivers activist Dawn Walker to replace the retiring MP Jan Barham, with more than 40 complaints lodged over the way the campaigns were conducted.

Ms Walker defeated Kelly Marks by 13 votes after preferences were distributed, which would make her the second candidate from the so-called right of the party to enter Parliament after Justin Field replaced the late John Kaye in August.

The two preselection battles have congealed tensions within the party, with both winning candidates allied to Mr Buckingham, a "tree Tory" centrist, which has disenfranchised the hard left alliance that is disparagingly referred to as the "eastern bloc".

This group lost its unofficial leader with the death of Mr Kaye from cancer in May last year, which has ruptured  traditional power structures. Last month a group calling itself the Left Renewal and calling for the end of capitalism became the party's first formal faction.

Returning officers for the December preselection said they were unable to declare Dawn Walker the winner until all complaints were resolved.

Woollahra convenor Ian Rose emailed all branches on Tuesday night, putting them on notice that he would take legal action if Ms Walker was confirmed as the preselection winner before the State Delegates Council considered the returning officers' report in February.

His solicitor wrote to the Greens' public officer on December 20 requesting that all notices indicating the Ms Walker had been selected be removed from Facebook and the Greens website.

Mr Rose, who was secretary of the NSW Greens last year, warned that the Greens were at risk of falling into the "whatever it takes" style of politics that characterised the major parties.

"In my opinion there are real and well-founded concerns that the last preselection suffered from a serious and systematic disregard for the rules which give all candidates a level playing field," Mr Rose wrote.

"If we do not examine what has happened in this preselection and put a stop to this behaviour, we run the very real risk of losing our reputation for integrity."

The PDC found that Mr Buckingham had breached party rules by making a "comment" on the preselection under a strict interpretation of the rules, but the email was not an endorsement of any candidate.

It recommended amending the rules to allow MPs to make comments that are not endorsements.

However, it found that Mr Buckingham had been misleading when he claimed to have used a personal email list to send the message and not a party-privileged database.

"The PDC is unimpressed with parts of Jeremy's response and notes that he did send the email in his role as an MP (email address and signature), and trying to convince the PDC that he sent it from a privately compiled database lacks credibility," it ruled.

"However … we consider it purely a technical breach."

Ms Walker and Mr Buckingham declined to comment.