CANBERRA, Australia — Prime Minister Tony Abbott said Wednesday that Australians would get a chance to vote on legalizing gay marriage if they re-elect his government next year — a promise his opponents argue is a stalling tactic to sideline the divisive issue ahead of the general elections.

Abbott's ruling conservative coalition all but doomed legislation that would allow gay marriage by refusing to allow its lawmakers a free vote on the issue.

Coalition lawmakers voted at a meeting Tuesday night saying members had to follow the party line that marriage should be lawful only between a man and a woman.

The outcome is a victory for Abbott, a former Roman Catholic seminarian who has been described as Australia's most socially conservative prime minister in decades. However, a vote on the legislation could damage his leadership if government lawmakers broke ranks to support gay marriage.

Abbott extended an olive branch to marriage equality advocates, offering to allow the public to vote on gay marriage in a plebiscite if his government retains power at the next election. Currently the governing coalition trails the opposition Labor Party in opinion polls.

"The only way to successfully and satisfactorily settle this matter, given that it is so personal and given that so many people have strong feelings on either side of this — the only way to settle it with the least rancor, if you like, is to ask the people to make a choice," Abbott told reporters.

"That means that going into the next election, you'll have the Labor Party which wants it to go to a Parliamentary vote and you've got the coalition that wants it to go to a people's vote," he said.

Abbott has changed his position since May when he ruled out an Australian popular vote after an Irish referendum in which 62 percent of voters called for their constitution to be changed to allow same-sex marriage.

Despite the ruling party decision, one government lawmaker, backbencher Warren Entsch, plans to introduce a private-member's bill to Parliament on Monday that would allow same-sex marriage. But Enstch and other supporters concede that any bill will fail because government lawmakers will not be allowed to vote freely.

Opposition leader Bill Shorten, who introduced a same-sex marriage bill in June, has not given up hope that the Parliament will legalize gay marriage before the next election.

"When it comes time, if he gets re-elected at the next election, you can forget about marriage equality," Shorten said. "The choice in this country is you either have Mr. Abbott or you have marriage equality. But you can't have both."

Some members of the ruling Liberal Party are angry that Abbott allowed their junior coalition partners, the Nationals — a more conservative, rural-based party— to take part in the decision over gay marriage.

Senior ministers Malcom Turnbull and Chris Pyne had argued for a free vote. They would have to quit Abbott's cabinet if they broke ranks and voted for a gay marriage bill, although Abbott suggested "it is unusual" for bills not sponsored by governments to go to a vote.

Federal plebiscites, which unlike referendums carry no legal weight, have occurred on only three occasions since the Australian government was formed in 1901. Two plebiscites rejected conscription during World War I. A third in 1977 replaced "God Save the Queen" with "Advance Australia Fair" as Australia's national anthem.