The results upended pre-election polls which predicted a Labor victory, though it is unclear whether the Scott Morrison-led coalition can govern with an outright majority or will need to negotiate support from independents.

The final result may not be known for some time.

"I have always believed in miracles," Morrison told cheering supporters at Sydney's Wentworth Hotel, where the government holds its official election night function.

"Tonight is not about me or it's not about even the Liberal party. Tonight is about every single Australian who depends on their government to put them first."

The conservative government has won or is leading in 72 seats in its quest for a 76-seat majority, according to the Australian Electoral Commission.

Several seats are still too close to call and the final result is complicated by a large number of early votes that have delayed counting.

Morrison's coalition defied expectations by holding onto a string of outer suburban seats in areas where demographics closest resemble America's Rust Belt, blocking Labor's path to victory.

This included a devastating result in the coal-rich state of Queensland, which backed the Pentecostal church-going prime minister by defying expectations and delivering several marginal seats to his government.

Labor leader Bill Shorten said late on Saturday he could not win enough seats to form a government. Speaking to supporters in Melbourne he said he would step down as party leader.

REUTERS