Scott Morrison looks set to be returned as prime minister leading a minority government, with Labor unlikely to pick up enough seats to win a majority.
The Liberal-National Coalition has surged ahead in a tight federal election, seizing Labor seats in Tasmania, Queensland and NSW.
At 9.30pm, it appeared the Coalition was holding 73 seats to Labor's 65, with eight seats in doubt.
However, former prime minister Tony Abbott has become the biggest casualty of the day losing his northern beaches seat of Warringah to independent Zali Steggall.
The crossbench is set to include at least independents Andrew Wilkie and Ms Steggall, Katter's Australian Party leader Bob Katter, the Centre Alliance's Rebekha Sharkie and the Greens' Adam Bandt.
Mr Abbott conceded defeat just before 7.30pm after 25 years in the seat, with Labor calling the Sydney result a “slaughter”.
Home Affairs Minister Peter Dutton has held onto his seat of Dickson in Queensland after clinging to it with a thin margin of 1.7 per cent, News Corp reports.
Barnaby Joyce is also expected to hold his seat of New England in NSW, according to the ABC.
Labor has managed to win the NSW South Coast seat of Gilmore from Liberal’s Warren Mundine, the ABC reports.
However, Liberal ousted Labor’s Diane Beamer from the Sydney seat of Lindsay.
Coalition wins the battle of Queensland
The Coalition is seeing poor results in Victoria, with Queensland holding firm, and Tasmania showing some promise for gains.
Labor is struggling to have an impact in the state, where a slew of marginal seats were up for grabs and was the focus of heavy campaigning by both sides.
Liberal’s Terry Young has wrangled the seat of Longman in Queensland from Labor and George Christensen is expected to be returned in Dawson without any problem.
"It's been tough in Queensland for a fair while for Labor federally," Labor senator Penny Wong told the ABC.
"We always thought that was going to be a state where the margins of some of the seats, notwithstanding where the two-party preferred nationally was, would mean that we would have a tough time."
The Coalition is also likely to claim the seats of Bass and Braddon in Tasmania, where Prime Minister Scott Morrison visited on election morning.
First-time candidate Gavin Pearce ousted Labor incumbent Justine Keay in the seat of Braddon.
Mr Pearce, a beef farmer and former soldier, declared victory at 9.30pm with a swing of 5.8 per cent towards the Liberals.
Ms Keay won Braddon in 2016 on a slim margin of 1.7 per cent.
Bass is expected to also return to the Liberals, with a 6.7 per cent swing to George Town mayor Bridget Archer over Labor incumbent Ross Hart.
Western Australia was expected to rally for Labor but the swing did not eventuate.
Opposition leader Bill Shorten was earlier tipped to lead Labor to victory in Saturday's federal election with a swing of 2.4 per cent, according to a Nine/Galaxy exit poll.
But the patchiness of swings across the states had some commentators speculating of a closer than expected result.
"There is nothing in the numbers at the moment which we're indicating we're about to see a big swing to the Labor Party," ABC analyst Antony Green said.
"We're not seeing Labor waltz into office as some people expected to see tonight."
Labor's best showing appears to be the Victorian Coalition seats of Dunkley, Chisholm, Higgins and Corangamite and La Trobe.
Greens could determine who forms government
Greens leader Richard Di Natale says the party could determine who forms government if it wins the key seats of Higgins and Kooyong.
Senator Di Natale says the election itself and the result in the two Melbourne seats are too close to call.
"Those two seats could determine who the next government of this country is," he told the Greens' election function.
"They could be the seats that form government.
"If Higgins and Kooyong become Greens seats, we could determine the fate of the country – and that is a live question right now."
Senator Di Natale is confident the Greens will retain their strength in the Senate, where six of their nine senators are up for election.
‘I’d rather be a loser than a quitter’
Mr Abbott was elected to the northern beaches seat of Warringah in 1999.
Former Liberal deputy leader Julie Bishop said Mr Abbott would have to get a primary vote of about 44 per cent in order to win, but was only sitting on 32 per cent just after 7pm.
Tony Abbott addressed his supporters at Manly Leagues Club just before 7.30pm tonight. He told them he had good news and bad news.
“The good news is that there is every chance that the Liberal-National Coalition has won this election,” he said.
“So of course it's disappointing for us here in Warringah but what matters is what's best for the country. I do congratulate Zali Steggall on what is a magnificent win for her.”
Mr Abbott said he knew it was going to be a challenge this election but “it doesn’t hurt to lose.
“I’d rather lose than be a quitter,” the former prime minister said.
“It's often said that all public lives end badly. But I'm certainly not going to let one bad day spoil 25 great years.”
‘Referendum for Warringah’: Steggall says
Ms Steggall arrived to a rockstar reception at the Novotel hotel in Manly.
She described the night as "a referendum for Warringah".
"We've worked very hard for the past four months to make this happen – I think it's democracy," she told reporters.
"Politics in Australia has not been at its best for the past 10 years and it's time we changed that. I really take that on board and I take great responsibility for that."
Ms Steggall told reporters “Warringah has definitely voted for the future”.
“This is a win for moderates with a heart,” she said.
"I would like to pay tribute to Tony Abbott who has been a dedicated and long-serving local member – nobody can doubt his community spirit his work ethic and his contribution to this."
Just over 10 million Australians cast their ballots on Saturday at more than 7000 polling stations, following a record 4.76 million early votes cast and about 1.5 million postal votes.
Voting is now closed in all states and territories.
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