A Labor source had a different take: look at the bookmakers.

The Greens have been favourites with the bookies for the entire campaign, and though the odds have backed off slightly they remain comfortably in front.

"It's an uphill battle but Ged Kearney and the Labor team, they're giving it every shot," Bill Shorten told reporters on Wednesday.

If Labor loses the seat David Feeney vacated after misplacing his citizenship paperwork, it won't be for lack of trying in this by-election.

Kearney is a high-profile union leader who lives in Melbourne's inner north and has spent years fighting for left-wing causes.

Labor has promised to extend the number 11 tram line and has the backing of Catholic schools angry with funding reforms.

And the Greens have picked a perennial candidate who is facing scrutiny the minor party in Victoria is not used to.

Alex Bhathal has run and lost in Batman five times before.

Glass half-full? The Green vote has steadily increased since 2001 and she topped the poll on primary votes in 2016.

Glass half-empty? She's couldn't even manage to win a Green-leaning seat when Feeney forgot he owned a multi-million dollar investment property.

The Green campaign was rocked when a 101-page dossier of internal complaints about Bhathal was leaked to the media.

Greens leader Richard Di Natale backed his candidate.

"The complaints were considered very carefully by the Victorian Greens and what they have resolved to do is completely back Alex Bhathal as their candidate for Batman," he told reporters.

Bhathal said "no" when asked if she was a bully and also denied branch stacking.

But some in the branch say Bhathal has a cult following and she created a toxic environment.

The bullying issue dominated the Green campaign but, luckily for them, a set of other questions were constantly lobbed at Labor too.

Kearney had to face regular awkward questions about her party's stance on refugees and the proposed Adani coal mine.

Shorten walked the tightrope of sledging Adani in Batman while not ruling anything out when in Queensland.

A Green win might take the Adani headache away for Labor - the party can let the mine's owners live and die by whether they can get the finance.

But losing inner Melbourne to the Greens presents a greater existential threat to Labor, who have already lost the CBD at both state and federal levels.

The Victorian Labor government has tried to appeal to Green voters in the area for three years without a lot of success.

Will those voters ever go back to Labor?

For the Greens, Adam Bandt will get a desk buddy and the party will be in a good spot to hold the balance of power in any potential hung parliament.

But the internal disunity and leaking to the media represents another step in the party's evolution - and one the Greens' elders may not appreciate.

Now that seats are suddenly more winnable, there is internal pressure on which candidates get selected.

With internal pressure comes external scrutiny, and the disgruntled local branch members have already seen just how far a little leak to the media can go.

Australian Associated Press