What you need to know about postal vote

KEY DETAILS ABOUT POSTAL SURVEY ON SAME-SEX MARRIAGE:

* The package sent to all Australians on the electoral roll will include a reply paid envelope.

* Any extraneous material placed in the envelope will be destroyed and the survey form may also be destroyed.

* Lost or spoilt survey forms can be replaced.

* Those not wishing to participate are encouraged to destroy the form.

* Surveys will be barcoded, but will only be used for "mark-in" purposes.

* Arrangements will be made to allow remote Australians, those living in Antarctica and those deployed overseas to participate.

* The result will be published on the ABS website on November 15 and broken down along electorate and state lines.

* Observers will be nominated by parliamentarians to monitor key steps in the process.

TIMELINE:

* SEPTEMBER 12: Start of mail-out.

* OCTOBER 11: Requests for replacement surveys closes.

* OCTOBER 27: The date voters are strongly encouraged to post their form back by.

NOVEMBER 7: Responses received after this date won't be processed.

NOVEMBER 15: Result released.

(Source: Australian Bureau of Statistics)