Around a quarter of Australians are still to vote in the marriage plebiscite, according to data released on Friday by the Australian Bureau of Statistics.
The ABS estimates that 74.5 per cent of eligible voters, or 11.9 million people, have returned their survey forms.
The number is a marked increase on the estimate the ABS released last week, which showed only 67.5 per cent had participated.
The latest advertisement from the Coalition for Marriage
The reason may rest in a new methodology that counts actual forms scanned, instead of the weight-based approach the ABS had previously employed.
The bureau says that it received 300,000 forms last week, not the 1.1 million the new estimate would suggest, indicating that previous estimates were probably too low.
Australians have until 6pm on November 7 to get their completed forms to the ABS.
The result will be declared on November 15.