A vote to ban property developers from serving as councillors has passed the NSW Legislative Council.
The vote was carried 23 to 18, with Liberals and Nationals members voting against the ban.
Labor supported the Greens Amendments to allow the vote to be passed in the Upper House of Parliament.
The vote will now go to the Lower House of Parliament.
Labor's spokesperson for Heathcote and Oatley Mark Buttigieg MLC said Labor believes it is essential to protect the integrity of the decisions made by elected councils.
"We need to ensure that dodgy developers cannot make planning and development choices that poorly impact our local communities," he said.
"Labor Party policy for some time has been that property developers should not serve as councillors. Our party's rules ensure property developers cannot be selected or endorsed as a candidate for public office."
A NSW government source said Liberal and National Lower House members would want to look at the proposed legislation closer before deciding on it.
"There is a safeguard in place that currently councillors are not dealing with Development Applications. Instead, they go to independent planning panels," the source said.
Mr Buttigieg said that safeguard had not worked.
"Planning panels don't take away the ability for people to give advantage to themselves," he said.
"Where the big windfall is the knowledge of rezonings and knowledge of planning proposals and access to knowledge that the public doesn't have. That's an unfair advantage to developers and real estate agents who may also be councillors.
"If the Liberals were serious about developers not serving as local councillors, they would have changed their own party rules to ban them from running as endorsed Liberal Party candidates, and they haven't."
Mr Buttigieg said the Liberals and the Nationals would have the opportunity to do the right thing when they vote in the Lower House of Parliament.
"If the Liberals fail to do the right thing, I will continue in Parliament to pursue the issue of banning property developers serving as councillors," he said.
"It is not right that communities can be poorly impacted by individuals with a clear conflict of interest."