Western Sydney has topped the nation for 'no' votes in the same-sex marriage survey, resulting in NSW overall returning the lowest 'yes' result of any state or territory.
The postal survey results, released on Wednesday, revealed 57.8 per cent of NSW participants said 'yes' compared to 61.6 per cent Australia-wide.
The NSW 'yes' result was dragged down by much of western Sydney voting 'no' in a big way.
Blaxland, at the foot of the Blue Mountains, returned the nation's highest 'no' vote with 73.9 per cent of respondents opposed to gay marriage.
The neighbouring electorate of Watson was the only other division with a 'no' response of almost 70 per cent.
Nearby McMahon (64.9 per cent 'no'), Werriwa (63.7) and Fowler (63.7) also recorded very high rejections of gay marriage.
"I'm not surprised, Blaxland is a very socially conservative electorate," local federal member Jason Clare told AAP in a statement.
"I've always known the views of my electorate on this issue and I've always been upfront with them about mine.
"Good people with good hearts can have different views on this important issue."
Australian National University demographer Liz Allen says the cultural background, religion and education level of western Sydney residents paints a picture of social conservatism.
"People from non-English speaking backgrounds, reporting higher levels of religion and religiosity, are less likely to support marriage equality," Dr Allen told AAP.
"That's a function largely due to the more traditional views and culturally diverse views and so it's not surprising, in fact, that we would see this result."
In the 2016 census, just 14 per cent of Blaxland residents said they had "no religion", compared to 30 per cent of Australians overall.
Some 29 per cent of people in the electorate identified as Islamic with just over 19 per cent Catholic.
Western Sydney federal MP Anthony Albanese believes the region voted 'no' due to the large ethnic and faith communities in the area.
"Whether that be the Islamic community or the Greek Orthodox or the Coptic Christians - they are groups that have strong views and have organised in their communities," the Labor frontbencher told 2GB.
The electorate of Sydney recorded the equal highest 'yes' votes in the nation with 83.7 per cent supporting gay marriage.
Grayndler in Sydney's inner south recorded the highest participation rate in NSW at 85.1 per cent, while Fowler recorded the lowest (72.4 per cent).
The state's older residents were the biggest participators with 89.8 per cent of people aged between 70 and 74 taking part in the survey.
NSW had more women taking part (81.3 per cent) than men (77.5 per cent).