The same-sex marriage ballot should be conducted entirely online, according to Western Australian sustainability expert Peter Newman.

Professor Peter Newman, from Curtin University, said the government was spending more than $120 million on something that was creating an immense amount of waste.

Professor Newman said the mass use of paper resources needed for the opinion survey would compromise our natural environment.

“In climate terms, every tree planted takes 50 tonnes of carbon out of the atmosphere. Cut it down, and it all goes back,” Professor Newman said.

Professor Newman.

“We should be doing all our voting online from here on out.

“We should be smart enough to recognise 20th century approaches in the 21st century are not only unacceptable but not sustainable.

“We need to not only be good local citizens but learn to be good international citizens, and this postal vote is just another example of us not being that.”

The Australian Electoral Commission said 16,005,998 ballot forms would be provided to eligible voters to participate in the non-compulsory vote.

According to the AEC, this is an increase of 123,210 voters from the 15,882,788 registered as of June 30 this year.

Ballot forms were mailed out from September 12, with votes to be returned by November 7.

Australian Bureau of Statistics media relations manager Michael Wilson said: “Voters should expect to receive a package containing voting forms alongside a reply paid envelope and instructions on how to complete the survey.

“Once the data is collected the survey material and envelopes will be securely destroyed within 60 days.”

Mr Wilson said the ABS had conducted measures to reduce the environmental impact.

“The paper used in the survey has been sourced from Australia and produced with the endorsement of the Forest Certification and Australian Forestry Standard Certification,” he said.

Victorian Greens Senator Janet Rice said she was not satisfied with these measures.

“The paper is sourced from our native forests, which destroys the habitats of many threatened species, like Tasmanian devils, giant freshwater crayfish and the swift parrot,” Senator Rice said.

“The whole premise of the postal vote is wrong; it subverts the will of the Parliament, it is non-binding and non-compulsory and, even if successful, we still will need to have a free vote in Parliament. Everything about it is wasteful.”