A supporter of same-sex marriage in Australia is pictured through a rainbow flag during protest near a counter-demonstration against same-sex marriage at a park in Sydney, Australia, September 23, 2017. REUTERS/Jason Reed

SYDNEY (Reuters) - Australia’s Bureau of Statistics said on Tuesday 9.2 million people, or 57.5 percent of eligible voters, have cast their votes in a ballot on whether same-sex marriage should be legalized.

Australians began voting last month in the non-binding poll, conducted by post, to inform the government on whether voters wanted Australia to become the 25th nation to permit same-sex marriage. The results of the poll will be declared on Nov. 15.

The first official update suggests a high turnout is likely despite the ballot being non-compulsory.

Turnout levels will go a long way in determining whether Australian Prime Minister Malcolm Turnbull can finally resolve a topic that has dogged his tenure as leader and threatened to split his center government along ideological grounds.

Low turnout would have seen the issue continue to dominate the political discourse whatever the result, underpinned by questions of legitimacy in a country used to compulsory voting.

The first official update on the progress of the same-sex marriage survey comes just a day after a Sky News ReachTel poll showed the ‘yes’ vote on track for a comprehensive victory.

More than 64 percent of those surveyed have sent back their ballot and voted ‘yes’, the poll showed, with a further six percent planning to support same-sex marriage.

A widespread victory may do little, however, to heal a divided the nation of 24 million people, which has split along religious and generational lines and at times has threatened to turn nasty, prompting parliament to strengthen laws preventing hate-speech.