"We are in Australia, everyone should be equal. But people do talk about the issue." As same-sex marriage postal surveys are stuffed in mailboxes across the country, the battle for hearts and minds will be as hard fought in places such as Hurstville, St Albans and Blacktown as anywhere else. These are suburbs that are home to large populations of Chinese-, Vietnamese- and Filipino-Australians, three of the nation's biggest Asian ethnic groups. Their views could help sway the vote on marriage equality. The Chinese community has been a particular target during the campaign. A string of pamphlets and fliers have been issued making homophobic claims about same-sex marriage, including one that said it was a "grave to the family bloodline". One reason they are being wooed is the community's size. Of the 16 million voters on the electoral roll ahead of the postal survey, more than half a million could be Chinese-Australians.

Last year's census counted more than 535,000 Australian adult citizens with Chinese ancestry. The two other major ethnic groups of East and South-East Asian descent were Vietnamese-Australians (175,000 adults) and Filipino-Australians (162,000). They are also more open to voting "no". University of Melbourne research has found that people from non-English-speaking migrant backgrounds are less likely to support marriage equality than other groups. Dr Ka Sing Chua, president of the Chinese Association of Victoria, believes that most Chinese-Australians are socially conservative and would vote "no" on the question of marriage equality. His personal view is that the Marriage Act should not be changed to included same-sex couples. "It's a very complicated question," he says. "I think at the end of the day, everyone should have an informed decision."

One outfit hoping to influence that decision is the Australian Chinese for Families Association. The group is led by Dr Pansy Lai, who rose to prominence when she collected 17,500 signatures from the Australian Chinese community opposing the Safe Schools program in NSW. Much of the ACFC's website is devoted to stopping Safe Schools. There are also translations of anti-gay marriage columns by people such as Tony Abbott and Andrew Bolt. While Dr Lai is a Christian, she has said that the Australian Chinese for Families Association is not religious. However, religion may play a major part in guiding how certain communities vote. Eighty-nine per cent of Filipino-Australian adults, for example, identify as Christian. Seventy-three per cent say they are Catholic. The Vietnamese also have a strong Catholic community. Archdiocese around the country have been urging their followers to vote "no". "I'm a practising Catholic, it's still ingrained in me that only a man and woman should be able to get married," says Serna Ladia, president of the Philippine Community Council of New South Wales.

"But my children will have a different opinion to mine." One group adding their weight to the "yes" campaign is the Asian Australian Alliance, which wants to counter the inflammatory messages being spread about same-sex marriage. Erin Chew, the group's founder and convenor, says Chinese-Australians were clearly being targeted by the "no" side of the campaign, which was painting the community in a negative light. "It says they are against equality, which is not true," she says. "As Asians we all know what being discriminated or vilified feels like, why would we want to perpetrate that on others?" While she agrees that views on same-sex marriage are often split in Asian communities between the young and old, Ms Chew says that many elders have actually shown support for marriage equality.

One such story doing the rounds on social media is of William and his Ba (Vietnamese grandmother), who supports her gay grandson having the right to marry his partner. Francis Voon, director of multicultural engagement for the Equality Campaign (which made the video), says it's important that same-sex marriage supporters from different ethnic groups are given the resources to "engage their own communities". With more than a month until the postal surveys have to be returned, both sides of the debate will continue to court votes where they can. Viv Nguyen, president of Vietnamese Community in Australia's Victoria chapter, says it is important that people exercise their democratic right to take part in the vote. "It's what the Vietnamese people are very strong about. It's why a lot of us are here," she says.

Ms Chew agrees. "This is one of the best times for us to ensure our voice is heard and show that we are willing to get more involved in the political process."