As counting continued on Saturday night, Labor was poised to win enough seats to again govern in coalition with Shane Rattenbury's Greens.

As of 8pm, neither party had claimed victory or conceded defeat.

The Greens could prove the story of the ACT election. They are set to win at least one or two seats, and there are some predictions the party could win as many as six seats in the next ACT Legislative Assembly.

The election defeat would consign Alistair Coe's Canberra Liberals to another term of Opposition.

The Liberals suffered a swing against them in their heartland southern suburbs electorate of Brindabella, with sitting member Andrew Wall in danger of losing his seat.

The Opposition clawed back some ground in Mr Coe's seat of Yerrabi, where the Liberals are on track to win a third seat in the Gungahlin-based electorate.

The Liberals hadn't conceded defeat at 8pm, with the party pinning its hopes on strong support from older Canberrans who elected to cast a paper ballot on Saturday.

But ABC election analyst Antony Green declared just before 8pm that he couldn't see how the Liberals could win the 13 seats needed to form a majority.

Mr Barr will hail the election victory as an endorsement of Labor's progressive agenda and its handling of the summer fire crisis and COVID-19 pandemic.

The Liberals tried to frame the election around cost of living and used a series of stunts copied from UK Prime Minister Boris Johnson's general election campaign to get their message across.

But Mr Coe struggled to explain how he would deliver his ambitious promises, including freezing residential rates for four years and halving elective surgery wait times.

He was criticised for failing to answer daily questions and instead speaking in slogans and talking points.

The rush of early voting in the first three weeks of the campaign meant that only about 80,000 people - about 30 per cent of the electorate - were left to cast their ballot on polling day.

Earlier on Saturday, Mr Barr appeared confident that Labor could be returned for a sixth-straight term.

He said Canberrans wanted a sensible government that could guide the territory through the fallout from the coronavirus pandemic.

"We've avoided outbreaks, we've managed the territory with open borders through this most challenging of years," Mr Barr said.

"As we look to the economic recovery, it's about jobs as the number one priority but [also] investing in public services.

"We've been clear throughout the campaign that we have a way of funding our commitments."

Mr Coe spent Saturday alongside Liberal candidates in electorates across the ACT as they fought for the last remaining votes before ballots closed at 6pm.

The Liberal leader posed for photos and the television cameras outside Gungahlin Marketplace, but did not speak to the media.

He declined The Canberra Times' requests for an interview throughout the day.

Mr Rattenbury was confident the party would win enough seats to again hold the balance of power in the next ACT Legislative Assembly.

Ginninderra MLA Tara Cheyne says Canberra voters haven't appreciated Mr Coe's stunts throughout the campaign.

"I've never had so many people come up to me to talk about the opposition leader," she said.

"I'm nervous but hopeful tonight will be really positive for Labor.

"That's certainly been the reaction at street stalls, knocking on doors and especially today."

Deputy Labor leader Yvette Berry said the results were looking very positive about 8pm.

She said the Greens' strong result could be attributed to people's growing concerns with climate change.

Brindabella MLA Mick Gentleman said he was pleased with Labor's strong showing in Canberra's south.

At 8pm, it was on track to snatch a third member at the expense of the Liberals.

"We have been working hard over the past four years investing in the south," he said.

"They have also felt a bit safer after the bushfires, storms and covid than some of the other areas."

While Brindabella is often considered a Liberal heartland, Mr Gentleman said it was prone to move around.

"I think they look at the policies of both major parties and the Greens and they make their decisions on what's best for their future," he said.