YOU can’t fail to have noticed we’re soon to have a postal vote on same-sex marriage. But it’s the people who don’t vote who, paradoxically, could have the biggest impact on the poll.

Approaching one million Australians who could vote are not enrolled to do so. If that ‘missing million’ don’t sign up to the electoral roll by midnight on Thursday they will be unable to take part in the marriage postal vote to be held from next month.

On Thursday, the Australian Electoral Commission confirmed 54,545 people had added their names to the roll since the marriage survey was announced.

A further 577,879 people already on the roll have amended their details, most to ensure their ballot papers are sent to the correct address.

Despite the surge, the numbers are still way down on the 132,000 people who signed up to the roll prior to the 2016 federal election that saw the Coalition cling to power.

The ‘yes’ to same-sex marriage campaign is encouraging these ’silent swingers’ sign up to the roll as they fear a postal survey may intrinsically favour older voters who are more likely to stick with the current definition of marriage.

The AEC estimates that there are still around 800,000 people who are estimated to be ‘missing’ from the electoral roll.

That may not seem a lot but it could make a critical difference. At the 2016 election just 96,000 votes separated the two parties on the two party preferred tally.

The federal government announced the $122 million same-sex marriage postal survey earlier this month, to be run by the Australian Bureau of Statistics pending a High Court hearing in September.

An Essential poll published on Tuesday found 57 per cent of voters favoured changing marriage laws, while 32 per cent were opposed. Read more via news.com.au