Liberal Candidate for Port Stephens Jaimie Abbott was forced to apologise to Labor MP Kate Washington on Friday after it emerged one of her volunteers had been using fake Facebook profiles to troll the Labor campaign.
The extraordinary development came after Facebook deleted seven profiles connected to Tasman Brown, a parliamentary staffer of Liberal Duty MLC Catherine Cusack.
Facebook took the action after investigating a complaint from Ms Washington who claimed Mr Brown had been operating fake profiles in the marginal seat in recent months.
The Clerk of the NSW Parliament is also investigating a separate from Ms Washington which alleges Mr Brown’s online activities were a breach of parliamentary resources.
Mr Brown denied operating the fake accounts when he was first approached about the claims a fortnight ago.
It is believed to be the first time that Facebook has taken action in Australia on a complaint about online activity related to an election campaign.
A Facebook spokesman said the action had been taken because Mr Brown's use of the social media platform breached its conditions of use.
"We take a strong stand against people that attempt to mislead others about who they are or what they’re doing. We are constantly improving our capabilities to identify and remove violating activity through a combination of automated and manual investigations,” a Facebook spokesman said.
The Herald was unable to contact Mr Brown, who has been removed from the Liberal campaign, for comment on Friday.
Ms Cusack, who strongly defended her staffer when the claims first arose, confirmed she had spoken to Mr Brown following Facebook's intervention.
"I was misled, I'm very disappointed," she said.
"Tasman is absolutely passionate about politics and I believe that led him to make this mistake. I have counselled him about it."
Ms Cusack said she would not be taking any further action on the matter until the Clerk of the Parliament had concluded the investigation into Ms Washington's complaint.
"We will cooperate fully with the Clerk. At this stage we have not heard anything," she said.
In addition to using fake profiles, Mr Brown also had access to Ms Abbott's personal account. The account was among those which Facebook deleted.
Ms Abbott, who said she was unaware of Mr Brown's activities, rang Ms Washington on Friday afternoon to apologise for the activity.
"Tasman has admitted to me that that as a volunteer on my campaign he was responsible for making multiple Facebook posts about the campaign under a number of names," she said.
"Elections should be a contest of ideas rather than a race for likes on social media and I think that Tasman forgot this. I am deeply saddened and disappointed that this has taken place and that we were all misled."
The Liberal Party has lodged a counter-complaint against Ms Washington with the Electoral Commission for allegedly misusing the electoral roll to research the identity of the fake Facebook profiles.
Ms Washington challenged the Ms Abbott and the Liberal party on Friday night to reveal was was known about Mr Brown's online activities.
“It takes real moral cowardice to try and sheet home all the blame for this scandal to a political staffer. It’s also completely illogical," she said.
“Ms Abbott needs to come clean on her role in this coordinated campaign to smear me and my credibility on Facebook. She has proven herself unsuited to parliament. I think the appropriate thing to do is to stand aside and relinquish her candidacy. Failing that, the Premier should move to have her dis-endorsed."
“When I referred this matter to Facebook and the Parliament last week, the Liberals categorically denied it and viciously attacked me instead. They are only admitting this now because they’ve been found out, and they’re trying to pin it all on a staff member."
Ms Washington also called for a so-called Liberal Party 'dirt unit' to be disbanded.
"The Liberals have set new lows for misinformation and manipulation in this election. They should show some civic responsibility and respect our democratic traditions."
A Liberal Party spokesman said the party would not be commenting on the matter because it remained under investigation.