City of Sydney councillor Christine Forster, an advocate for the 'Yes' campaign, labelled the decision to provide free facilities for same-sex marriage weddings as "reckless".
Labor councillor Linda Scott and Lord Mayor Clover Moore moved a motion on Monday night to allow gay and lesbian couples to marry in the halls and facilities of Sydney for free if same-sex marriage was legalised.
The promise for free same-sex marriage weddings will last 100 days, but will not affect the existing bookings of heterosexual couples already using the facilities.
But Cr Forster voted against the motion because it goes against everything the Marriage Equality campaign has fought to achieve.
"You can't replace old discrimination with new discrimination," Cr Forster told SBS News.
"This has been a fight all about equality for everyone before the law. So to me, it flies in the face of the core principles we've been fighting for.
"I tried to change this motion on the floor of councils so it included all couples, but that was defeated by Clover Moore and the Labor councillor [Linda Scott]. But really I think it's wrong that we exclude heterosexual couples, that is discriminatory."
Liberal Party Councillor (And sister of Tony Abbott) Christine Forster and Partner Virginia Edwards, while attending a Same Sex Marriage "Yes" campaign event. Source: AAP
Cr Forster hoped the "reckless" decision did not persuade any late voters to change their mind after the 'Yes' campaign's tireless efforts.
"It would be truly terrible if this reckless decision, a reckless move by the City of Sydney Council, persuaded even one voter not to vote yes," she told SBS News.
"This just sends the wrong signal."
"What we have been fighting for is marriage to become more inclusive, not exclusive. It's been exclusive in the past.
"The reality is we should be inviting every couple that wants to get married, under an amended marriage act if that's what happens. We want to be able to celebrate all marriages."
The Lord Mayor of Sydney Clover Moore said in a statement the decision was simply rebalancing the scales.
Christine Forster posted a response following the City of Sydney decision. Source: Facebook
"We’re making this gesture in the spirit of celebration and welcoming same-sex couples to this institution, to which they have been denied access so long -- we are simply doing what we can to rebalance the scales," she said in a statement.
"And the day after the amendments become law - we will also work with the Sydney Registry of Births, Deaths and Marriages to hold a mass same-sex wedding extravaganza in Sydney Town Hall."
The Coalition for Marriage released a response slamming the decision claiming ratepayers could be funding the celebration of same-sex weddings.
"By promising to continue its already extensive and expensive 'Yes' campaign advocacy even if a 'Yes' vote prevails, the City of Sydney is sending a clear message that a change in marriage law will have consequences for everyone, including ratepayers whose money will be used to fund the celebration of same-sex weddings," a statement to SBS News said.
"Many Sydney residents are rightly concerned about the impact of gay marriage on free speech, freedom of belief and their ability to protect their kids from exposure to MA-rated materials in school.
"This gesture indicates that the City of Sydney is ignoring the serious concerns held by many Sydneysiders."
The result of the same-sex marriage survey will be released on November 15.
If it's a 'Yes' vote, Prime Minister Malcolm Turnbull has promised to allow a private member's bill to be introduced to the parliament in the final sitting fortnight of 2017 to change the definition of marriage.
That is the last week of November and the first week in December, meaning same-sex marriage could be legal in Australia by Christmas.
SBS News has contacted the City of Sydney Council for comment.
