The City of Sydney has passed a motion allowing same-sex couples free council venue hire for their weddings for 100 days after the legalisation of same-sex marriage.

The city’s halls, parks and facilities would be available to the couples at no charge but other expenses such as catering would still be the couples’ responsibility, Fairfax Media reported.

The offer would not be extended to straight couples, but no existing bookings would be affected.

Liberal councillor Christine Forster, who is gay and a prominent “yes” campaigner, opposed the motion after trying to amend it to also include straight couples’ weddings.

“This has been a fight for equality before the law and it’s my belief that we can’t ask for equality for ourselves and then deny it to others,” Forster said.

“It’s also been about making marriage inclusive, not exclusive, and this motion flies in the face of that.”

Labor councillor Linda Scott, who moved the motion, said an offer just for same-sex couples was not discrimination because the LGBTI community “has suffered significant discrimination and many have felt hurt during the campaign.”

“This is a practical way for the council to combat discrimination,” she said.

Sydney Lord Mayor Clover Moore threw her support behind the motion and said the council had been approached by the Registry of Births, Deaths and Marriages to hold a mass same-sex wedding at Sydney Town Hall after the reform is legalised.

The result of the same-sex marriage postal survey will be announced by the Australian Bureau of Statistics on November 15.

Prime Minister Malcolm Turnbull has said the government would move on the issue before the end of the year if a majority “yes” vote is returned, and the legislation would “sail through” the parliament.

A private member’s bill by Liberal Senator Dean Smith and others has the backing of Labor and LGBTI advocates.

But some conservative politicians and “no” campaigners have demanded stronger exemptions to discriminate against same-sex couples on the basis of religion.