Support for marriage equality has rebounded and the yes side holds a decisive lead among Australians who have already voted in the postal survey, according to the Guardian Essential poll.
The poll found that 58% of Australians support a change in the law to allow same-sex couples to marry, up three points from 55% last week, compared with 33% who oppose it and 9% who are undecided.
More than one-third of Australians (36%) have already voted, with many more saying they will definitely vote (45%) or probably vote (8%).
Among those who have already voted, 72% voted yes compared with 26% who voted no.
Yes voters also outnumbered no voters in the “will definitely vote” category (57% to 39%) and “will probably vote” (43% to 35%). Among people who say they will not vote, 64% said they did not support same-sex marriage and just 13% said they did.
The results of the poll, if replicated in the survey, would deliver a decisive win for marriage equality, although advocates have warned campaign efforts must be sustained until the 7 November deadline for votes to be received by the Australian Bureau of Statistics.
The Equality Campaign executive director, Tiernan Brady, said: “Undoubtedly these numbers are really good … however, it is only a poll and we are in no way complacent.”
“We know that the Australian people are for marriage equality and have been for many years but for that value to be reflected in the result of the survey everybody needs to vote.”
The Guardian Essential poll found a majority of women (63%), men (52%) and even people over the age of 55 (54%) supported changing the law to allow same-sex couples to marry.
Greens voters were the most likely to have already voted in the postal survey, with 49% already having done so, and 84% of Greens said they supported marriage equality, adding evidence that “hard yeses” had turned out early.
The poll finds Labor and the Coalition tied on primary votes of 37% while Labor leads the Coalition 53% to 47% in two-party preferred terms, a slight increase from last week’s 52-48 result.
The Greens are steady on 10%, the Nick Xenophon Team steady on 3% and One Nation dropped one point to 7%. The poll of 1,026 Australians has a margin of error of plus or minus 3%.
Asked if they are concerned same-sex marriage may impact on religious freedoms, 35% were either very or somewhat concerned compared with 58% who were either not very or not at all concerned.
Over the course of the campaign 24% said…