Labor is ahead of the Greens for the seat of Brisbane by just 34 votes for the hotly contested electorate.
But postal votes, which are still being counted, are favouring Labor candidate Madonna Jarrett over her Greens rival Stephen Bates.
Ms Jarrett had received 21,931 votes on Tuesday evening, compared with Mr Bates who had 21,897 tallied.
Outgoing LNP MP Trevor Evans received the most primary votes, but conceded defeat on Saturday night.
The Greens declared victory in the Brisbane seat of Griffith, winning it from Labor’s environment spokeswoman Terri Butler.
The progressive party also won the inner-city seat of Ryan in Queensland’s capital, with leader Adam Bandt hailing a “greenslide” in its “best result ever”.
Despite those gains, Prime Minister Anthony Albanese – who returns on Wednesday from the Quad meeting in Japan – is still on track to form a government in his own right.
The final tally is expected to show Labor holding 76 seats to 61 for the coalition, with 14 crossbenchers.
This would mean Labor gained eight seats, with the coalition losing 16 compared with the 2019 federal election.
As of Tuesday afternoon, former minister Michael Sukkar led the contest for the Victorian seat of Deakin by 74 votes against Labor hopeful Matt Gregg.
Former NSW minister and Liberal candidate for Gilmore, Andrew Constance is 105 votes ahead of sitting Labor MP Fiona Phillips.
In the Senate, the coalition is on track to hold 30 seats, and Labor 25, in the 76-seat chamber from July.
Labor will need 14 extra votes in the upper house to pass legislation, relying on the Greens for support.
One Nation leader Pauline Hanson is set to retain her Senate spot for Queensland.
But billionaire Clive Palmer will not win a Senate seat, despite splashing about $100 million on his United Australia Party campaign.