Millions of Aussies are preparing to head to polls for the Voice to Parliament referendum on Saturday - but don't expect to find out the result of the national question on the night.
The Australian Electoral Commission (AEC) confirmed approximately four million ballots have already been cast at early voting centres across the country.
Despite the rush of early votes, ballots won't be counted before polls close and an outcome will never be officially declared on the night of a referendum, in line with federal elections, according to the AEC.
While electoral analysts and commentators are able to provide an indication of the results depending on how close the margin is, each ballot must undergo a vigorous counting process.
The AEC is required to count each ballot paper more than once in the days after the referendum night in a process called "fresh scrutiny".
Overseas votes, postal votes and votes made outside of a person's home electorate can also delay the result as they take time to transport to local counting centres.
On top of this, each aspect of the double majority for the referendum has to be mathematically certain before the AEC can officially make a declaration or the return of the writ.
How Australia voted in all 44 of the nation's referendums
To succeed, a referendum needs the majority of people and the majority of states (what's known as a double majority) to vote in favour of a Yes-No proposal.
"The AEC conducts a referendum count very similarly to the House of Representatives count at a federal election," the electoral authority says on its website.
"Like in a federal election, if the overall result is close it may require up to 13 days after polling night for a result to be known.
"This is the timeframe allowed under referendum legislation for postal votes to come back to the AEC for inclusion in the count."