Australians overseas or those living in aged care or in very remote areas will have the option to vote on same-sex marriage over the phone or online.
The Australia Bureau of Statistics on Tuesday released more details about the postal survey process amid concerns that some people could miss out.
It confirmed a paperless option will be available to Australians abroad during the collection period, living in a residential aged care facility or in very remote locations, and the visually impaired.
Those who are eligible can request an access code to anonymously respond to the survey via an automated phone service, online form or the information line.
The ABS also confirmed it will be providing instructions in 15 languages, interpreter services and help for people with hearing and speech impairments.
On top of that, there will be sites in capital cities from which eligible people can pick up survey forms.
"While we expect nearly all eligible people in Australia will receive their survey materials by post, we are implementing measures to make sure everyone has the opportunity to participate in the survey," deputy Australian statistician Jonathan Palmer said in a statement.
Mr Palmer reassured silent electors, whose addresses aren't visible on the electoral roll, won't have their details disclosed to the ABS, with the Australian Electoral Commission to post out their forms.
Those wanting to vote will have to be correctly enrolled with the AEC by midnight on Thursday.