"But it is absolutely clear that we have to get our own house in order if we’re going to win back traditional Greens voters who were turned off by the leaking and sabotage from a few individuals with a destructive agenda," he said.

The campaign was rocked in January by the release of a 101-page dossier of complaint against Ms Bhathal, as national infighting between the so called socialist "watermelon" faction and the more centrist politics of its leader moved from the national to the local stage in Batman.

The Greens leader avoided a traditional election post-mortem press conference on Sunday, opting only to go on ABC TV at 9pm - after the major national TV news bulletins and newspaper print deadlines.

The defeat has capped off a horror few months for the party; it lost two senators to the dual citizenship fiasco, and recently recorded its worst result in Tasmania in three decades. However Greens loyalists point out it also picked up its first Queensland lower house seat in December.

But Saturday's result has shaken party elders. In a text message to members, NSW convenor Hall Greenland said the defeat showed when Labor went left it would attract supporters the Greens thought they had secured.

"It happened in Tasmania and of course on an industrial scale in Britain after [Jeremy] Corbyn became leader," Mr Greenland said.

"This trend has been staring at us in the face for some time - I wrote about it six months ago - and can no longer be ignored."

Australian Electoral Commission data shows that the swing to Labor in the south of the seat - an area the Greens have dominated during the past two elections - was larger than the swing to the Greens in the north, where a higher proportion of Labor leaning working-class voters live.

As late as 6pm on Saturday, Labor had all but given up on reclaiming the area south of Bell Street, distributing demographic figures just minutes before the polls closed as a preface to why they might lose the seat.

But the final result showed a resounding swing back to Labor, as voters appeared to reward Opposition Leader Bill Shorten's gamble on divided imputation reform and punish the Greens for its flirtation with conservatives after it urged wealthy retirees to vote Green in protest.

Mr Shorten said warnings about the policy's impact on pensioners to the north and south of the electorate had fallen on deaf ears.

"When people voted yesterday, they know that the Labor Party wouldn't hurt pensioners and we are not going to," he said at press conference celebrating the win with Ms Kearney in Melbourne on Saturday.