The news comes as the Greens defended themselves on Tuesday against Labor’s attacks on the minor party’s culture and treatment of women, with Greens leader Samantha Ratnam invoking the #MeToo movement to defend her organisation.

ALP planners say their research shows the contest in Melbourne, won by Ms Sandell in 2014 after being held by Labor for more than a century, is close enough to justify extra spending with a realistic chance of winning back the seat, held by a margin of 2.4 per cent

If accurate, the Labor research shows a huge improvement in Labor's performance from 2014 when it was trounced on primary votes by Ms Sandell and relied on preference flows from the Liberals, who will not direct preferences in the current election, to get into a competitive position.

The Greens still say they can win enough inner-city seats against Labor to deliver the balance of power in the lower house, despite being forced on to the defensive by a ferocious Labor campaign of negative advertising and attacks by senior government figures.

Premier Daniel Andrews and some of his senior ministers, backed by a well-resourced advertising campaign, have exploited the Greens’ high profile gender issues.

The premier has labelled their rivals’ internal culture as toxic to women, as Labor looks to hurt the Greens' support among female voters.

A Labor campaign source said the party was treating its research in Melbourne with caution, because of the shortcomings of single-seat polling and the difficulty of accurately gauging voter intentions in inner-city seats.

But the ALP is sufficiently encouraged to throw more resources and volunteers behind its candidate for Melbourne, Jennifer Kanis, who held the seat between 2010 and 2014.

Ms Sandell said she always expected the seat to be close and was not taking any votes for granted.

"But it feels really positive when we're out at the train stations and at community events," she said.

"They [Labor] have definitely stepped up their attacks but we're keeping up our positive message."

Another Labor source said the tactic to highlight the Greens’ internal cultural problems, based on widely reported incidents, was potent because it was factually based.

“On gender issues, they [The Greens] can be appalling and that’s going to shock the sh*t out of people,” the source said.

“This stuff sends Greens women off their brains. As long as the material is factual, and it's got to be 100 per cent bullet-proof, then it’s fair game.”

The Labor figure said the Greens’ decision to stand by its candidate for the seat of Footscray, Angus McAlpine, despite his past as a rapper spouting misogynist lyrics, was not helping his party’s cause.

“We would dump one of our people in a non-second, if they’d done stuff like that,” the source said.

In a Facebook post on Tuesday, Ms Ratnam defended her party’s efforts at cultural change.

“As a social worker, I know very well that people have their flaws, but they can and do change, "the Greens leader said.

“You can trust that we are taking strong action and we are committed to creating the healthiest culture possible in our movement for environmental and social justice.

“The #MeToo movement has proven many things, one is the strength of women.

“The second is that we all need to take responsibility for this problem that exists society-wide. The Greens are not immune to that.

“As a party full of strong women, we must always strive to do more.”