On Tuesday, election officials began the task of counting more than a million postal votes, according to the Australian Electoral Commission, including for a handful of crucial seats which may decide who forms the next national government.
Officials said a final result may not be known for at least a week.
Australian Prime Minister Malcolm Turnbull has ignored calls to resign after a poor result for his Liberal/National Coalition government, who had been expected to retain a majority.
Speaking to reporters outside his home on Tuesday
, Turnbull told them he was still confident of holding onto power.
"The count is continuing and we remain confident that we will secure enough seats to have a majority in the parliament but all the votes have been cast, that's good news, and it's now simply a matter to count them," he said.
Australian National University political science professor Ian McAllister told CNN another election within a year was possible if neither major party could form a stable government.
"(But) the Coalition would not be keen on having another election because it would look bad for them and they would almost certainly do worse," he said.
Counting resumes in knife-edge seats
A spokesman for the Australian Electoral Commission told CNN vote counting began again on Tuesday, after concluding late on Saturday night, with at least a million postal votes still to be counted.
"How quickly that actually illuminates the whole picture, who forms government, we don't know. There's about six close seats... if (results) go about 50/50 for both candidates, we won't get any clearer pictures than we have now," he said.
The spokesman said if the vote remained tight, a result might not be known for two weeks.
According to the official count
, the Coalition government looks set to win about 67 seats while the opposition Labor Party may receive 71. Either party will need 76 to form government.
If neither party manages to gain a majority of seats, both will have to negotiate to form a minority government with the six, diverse independent members of Parliament, including the left-wing Greens party's Adam Bandt and right-wing maverick Queensland politician Bob Katter.
It would be Australia's second hung parliament in just six years -- former Prime Minister Julia Gillard
kept power after the 2010 election after making a deal with a small group of independent politicians.
Turnbull's future as leader at risk
Harsh recriminations have already begun between Australian conservatives over the decision to replace former leader Tony Abbott less than one year before the election.
Turnbull ousted Abbott in a leadership vote
among Liberal Party politicians in September 2015, promising to be more popular and stable than his predecessor.
On election night prominent conservative radio host Alan Jones called Turnbull supporter James McGrath a "bedwetter"
, while Coalition senator Cory Bernardi told Adelaide radio Turnbull needed to be "held to account."
Labor Party leader Bill Shorten
called for the prime minister to resign at a press conference on Monday, saying he was "not up to the job."
McAllister told CNN while Turnbull's position was not secure after Saturday's election, the lack of an obvious successor would make it difficult to replace him.
"People have talked about (Foreign Minister) Julie Bishop, but when Bishop was shadow Treasurer she wasn't a big success," he said
"Others have mentioned Treasurer Scott Morrison, who was the architect of the superannuation debacle... so he's on the nose with a lot of people in his party, but there's no obvious person in there who has been waiting."