Vote counting is set to continue just over a week since the federal election as winning MPs meet over the next few days to decide the ministers on Labor's side and leaders of the coalition parties.
Labor needs 76 seats to gain a majority in the lower house of federal parliament, with the party sitting on 75, according to the Australian Electoral Commission website.
The AEC considers three seats as in doubt - Deakin in Victoria, Lyons in Tasmania and Gilmore in NSW.
A fourth seat is also seen as tight by some pundits - the Victorian seat of Macnamara.
Liberal MPs will gather in Canberra on Monday and are expected to endorse Peter Dutton and Sussan Ley as the new leadership team.
Scott Morrison stepped down as party leader to return to the backbench after losing the prime ministership last weekend to Labor's Anthony Albanese, while Liberal deputy Josh Frydenberg lost his Victorian seat of Kooyong.
Mr Albanese said he won't underestimate Mr Dutton as opposition leader.
"I never underestimate my opponents," he told Sky News' Sunday Agenda program.
"I've been underestimated my whole life. I think there are some people who are regretting underestimating me over the last three years."Â
The Nationals leadership is less clear, with its party facing a three-corner contest.
Current leader Barnaby Joyce will face off against his deputy David Littleproud, who threw his hat in the ring at the weekend, and former veterans' affairs minister Darren Chester.
On Tuesday, the factions of the victorious Labor Party will meet in Canberra to thrash out who will sit on the government frontbench, and those ministers will be sworn in by the governor-general on Wednesday.
Former Liberal minister Michael Sukkar is 655 votes ahead of Labor's candidate Matt Gregg in Victoria's Deakin electorate, according to the AEC.
In NSW, sitting Labor MP Fiona Phillips is 214 votes behind Liberal candidate Andrew Constance in Gilmore, with postal votes slightly favouring the former state minister.
Labor incumbent for Lyons, Brian Mitchell, is ahead by 678 votes against Liberal candidate Susie Bower.
In Macnamara, Labor MP Josh Burns has taken a slight lead over his Greens rival Steph Hodgins-May with Liberal candidate Colleen Harkin trailing.
Respected ABC election analyst Anthony Green said AEC staff are processing declaration envelopes to be ready for a big count on Monday which should clarify the final result, unless seats remain ultra-close.