Australians voted in the closest national election in decades on Saturday with the country's first woman prime minister Julia Gillard neck-and-neck with conservative challenger Tony Abbott.
Polls opened at 8:00 am (2200 GMT) with 14 million electors taking part in a mandatory vote across the huge country, with last-minute opinion surveys showing only a minute gap between the two leaders.
A Newspoll published in The Australian newspaper gave Gillard's Labor a 50.2 to 49.8 per cent lead over the Liberal/National coalition headed by Abbott, raising the prospect of the first hung parliament since 1940.
A separate Nielsen poll put Labor ahead 52-48 per cent, while a Roy Morgan survey gave the government a 51-49 per cent lead.
Gillard's centre-left Labor has struggled to reassure voters after June's shock ousting of elected prime minister Kevin Rudd, lifting Abbott's hopes of a surprise victory.
"When everyone asked I said it would be a cliffhanger... and so it's proving today," Gillard said.
Gillard, 48, a red-headed former lawyer who was born in Wales, has pledged better education and healthcare and played up Labor's role in helping Australia shrug off the financial crisis, as well as a planned national broadband scheme.
Abbott, a 52-year-old religious conservative who has doubts about mankind's role in climate change, has targeted fears over illegal immigration and questioned Labor's spending record, as well as its knifing of Rudd.
{{/usCountry}}Abbott, a 52-year-old religious conservative who has doubts about mankind's role in climate change, has targeted fears over illegal immigration and questioned Labor's spending record, as well as its knifing of Rudd.
{{/usCountry}}The right-leaning coalition needs a swing of 2.3 per cent to return to power less than three years after Rudd ousted 11-year prime minister John Howard, pledging action on climate change and the impoverished Aboriginal minority.
Victory for Abbott would make Labor the first one-term government since 1932, when the party's James Scullin lost power during turmoil caused by the Great Depression.
Both sides are targeting a swathe of marginal seats in resource-rich Queensland -- Rudd's home state -- and western Sydney, where rapid population growth has put pressure on services and raised concerns about immigration.
As campaigning closed, Abbott looked to prove his credentials as a vigorous go-getter with a 36-hour overnight push from Thursday to Friday. On Saturday, he manned a beachside barbecue before casting his vote nearby.
"This is a big day for our country," Abbott said. "It's a day when we can vote out a bad government."
Most polls close at 6:00 pm (0800 GMT) Sydney time with the remainder two hours later due to time differences. The elections will decide the make-up of the 150-seat lower house and half the 76-seat Senate.
"I think it's too close to call at the moment. I think this is really, really tight," said Labor campaign spokesman Chris Bowen. "I think this will go right down to the wire and be the closest election in 50 years."