Election 2016: news, analysis and videoYourVote: where you fit with the major parties
More than 220,000 Australians cast ballots in the first three days of early voting for the federal election, well above the 183,000 who voted in the first week of pre-polling for the 2013 election.
Experts and the Australian Electoral Commission expect up to a third of voters could avoid polling places on   July 2, but early voters will be asked which eligibility criteria they meet in order to vote early. 
Electoral Commissioner Tom Rogers told a briefing at Parliament House on Friday that the 2016 poll would be one of the largest peacetime events in the nation's history, with 5 million NSW ballot papers to be counted in a single location.
About 95 per cent of eligible voters are currently listed on the electoral roll, meaning more than 15.67 million Australians will be required to vote.
Before the 2013 federal election, there were 14.71 million Australians enrolled to vote.
The commission is pleased more than 70 per cent of 18-year-olds are correctly enrolled in 2016, along with more than 80 per cent of 19-year-olds.
There are about 1.7 million enrolled voters aged between 18 and 24.
Changes to the Senate voting system and the double-dissolution could see the final results in the upper house unknown for days or weeks after the election, with the commission currently training staff in new vote-counting procedures.
Valid House of Representatives ballots must have every box marked in order of the voters' choice, while Senate ballots must have at least six boxes marked 1 to 6 above the line, or at least 1 to 12 below the line.
Mr Rogers said where a Senate ballot is marked with a "1" above the line and there are no other errors, it will be considered valid.
He said the commission was determined to meet the   August 8 deadline for return of the election writs, at which point the results of the poll will be finalised.
"We've got this huge undertaking and, frankly, we think it is probably one of Australia's largest peacetime logistic events," Mr Rogers said.
"It's a little like setting up a Fortune 500 company with three weeks notice, running it, and then dismantling it two weeks after the event."
"It could take us some time to finalise the rest of those results."
Changing security conditions and the bungled 2013 Western Australia Senate vote have seen improved background screening of some election day employees and so-called chain of custody arrangements for ballot papers.
Mr Rogers said the loss of 1300 ballot papers, which prompted a second Senate election in the state, prompted an overhaul of election day and counting procedures.
"We have also inculcated an ethos with our staff that ballot papers are valuable," Mr Rogers said.
"They're like a democratic blank cheque book, they're really valuable."
He confirmed the commission was yet to be officially notified of the government's plans for a national plebiscite on same-sex marriage in Australia in the second half of 2016.
It stood ready for a further electoral event within months of the election, but no actions would be taken until enabling legislation was passed by the Parliament, conditional on the Turnbull government being re-elected.
Mr Rogers said the legislation would determine if voting in the plebiscite would be compulsory, although it is expected the government would not consider a plan for non-compulsory voting.
Follow us on Twitter