A national poll has found that 75 percent of Australians believe legalization of same-sex marriage is inevitable.
Marriage-equality advocates responded by calling on political leaders to act immediately.
"The tide of history is running towards equality and nothing can turn it back," said Alex Greenwich, national convener of the group Australian Marriage Equality. "Our plea to the nation's leaders is to get on with this reform instead of unnecessarily prolonging a debate."
National polls show about 60 percent support for amending the Marriage Act to allow same-sex marriage.
The new poll, conducted May 27-29 by Galaxy Research and commissioned by Australian Marriage Equality and by Parents and Friends of Lesbians and Gays, found that 80 percent of women, 79 percent of people under age 50, 78 percent of people with young children, 71 percent of men and 68 percent of people over age 50 see legalization of same-sex marriage as inevitable.
The question asked was, "Do you believe it is inevitable that eventually the law will change in Australia to allow same-sex couples to marry?"
"Australia is ready for equality for our gay and lesbian children, so it's time for political leaders to act," said Shelley Argent, PFLAG's national spokeswoman.
Argent has launched a national TV ad campaign where she is seen decorating her son's wedding cake while expressing concern "we may never get to eat it."
"I'm ready, and so is the cake," she says. "Please, Julia ... give my son the choices and rights to emotional security and instant respect that comes from marriage."
Julia Gillard is the Australian prime minister. The ad is online at tinyurl.com/4397qys.
Galaxy Research questioned 1,052 Australians over age 18. Afterward, the data was weighted by age, gender and region to reflect the makeup of the country.