In early counting, the signs weren't good for Labor as several seats looked likely to fall to the coalition.
In Brisbane, Labour's Arch Bevis was facing a nailbiting contest against the LNP's Teresa Gambaro.
On a two-party preferred basis - with 9.68% of the voted counted - Mr Bevis was behind of 49.12% of the vote.
In the seat of Leichhardt, former Liberal MP Warren Entsch was expected to take the seat back from Labor's Jim Turnour.
With 4.75% of the two-party preferred vote counted, Mr Entsch had 58.41% of the vote, a swing of more than 12%.
Labor's Kerry Rea was also behind in the seat of Bonner, where she was facing a swing against her of 7%.
With 7% of the two party preferred vote counted, she was on 47.41% of the vote.
She is up against the LNP's Ross Vasta, who lost the seat in 2007.
Nationally, Labor was showing a swing against it of 3% on 47.03%, after the distribution of preferences.
The coalition was on 53.97% of the vote.
A swag of marginals in western Sydney and Queensland expected to determine the outcome of the extremely tight poll.
The latest Newspoll, published in the Australian newspaper, had Labor with 50.2% support against 49.8% to the coalition after the distribution of preferences.
The coalition needs 17 Labor seats to win the election by garnering a uniform swing of 2.3% across the country. But the government can lose its absolute majority if it loses 13 seats.
With 13 per cent of the vote counted, the Australian Electoral Commission had called 51 seats for Labor, 45 for the coalition and three for independent candidates. It had 51 still in doubt.
ABC election analyst Antony Green believes Labor would lose at least six seats to the coalition.
"I've got the coalition ahead in 13 other Labour seats, which brings you to 19," he said.
"I've got Labor gaining one seat, McEwen, and ahead in La Trobe. So at this stage there's a net shift of 17 seats, now that's still too close to call, some of those seats are doubtful but that means, at this stage, we'll be here for a long time yet."
There are swings against Labor in eight key marginals in Queensland and two in NSW.
Labor is in serious trouble in Macquarie in Sydney's west, where current Liberal Greenway MP Louise Markus is running following a redistribution.
With 12.7% of the vote counted, there's a 3.26% swing to the Liberal candidate Susan Templeman on a two-party preferred basis.
Labour notionally holds the seat by just 0.3 per cent following a redistribution.
In Sydney, former ABC journalist Maxine McKew is down in her fight to retain former prime minister John Howard's seat from the challenge of prominent former tennis player and commentator John Alexander.
With 20.4% of the ballots tallied, there's a 6.9% swing against Ms McKew on a two-party preferred basis. She holds the seat by a margin of just 1.4%.
Flynn, in Queensland, also looks like tumbling to the coalition.
With 32.2% of the vote counted, there's been a 6.15% swing against Labor to the LNP's Ken O'Dowd.
Sitting MP Chris Trevor holds the seat by just 2.2%
The central Queensland seat of Dawson is another where Labor trails.
With 27.3% of the vote counted, there's a swing against the government of 4.2%. Dawson is held by retiring Labor MP James Bidgood by just 2.6%. The LNP candidate George Christensen is up against Labor's new candidate, Mike Brunker.
In Forde, another key Queensland marginal, there's been a 7.18% swing against Labor on a two-party basis with 37.1% of the vote counted.
Sitting MP Brett Raguse looks in serious trouble, although his LNP opponent Bert Van Manen is yet to crack open the champagne.
