Fifteen local councils have passed a motion calling for the federal attorney general, George Brandis, to scrap his proposed changes to the Racial Discrimination Act.
The government wants to remove the words insult, offend and humiliate from section 18C, in a move it says will allow greater freedom of speech.
People have until the end of the day to file submissions to the government about the proposed overhaul.
The campaign group Project 18C says the five-week long period allowed for submissions hasn't been sufficient.
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One of its organisers, Erin Chew, says many Australians harbour concerns about the proposal.
"If the changes go through and are actually put in place the fear is, the idea of where does free speech end?
"Is there a limitation to what people can say? And what can people do if they are from a different background if they are targeted by people who are claiming to use free speech?"
Ms Chew says 15 councils in NSW and Victoria have passed the motion including Ryde, Parramatta, Hurstville, Canada Bay, Canterbury, Darebin, Moreland, the City of Melbourne, Glen Eira and Ballarat.
Erin Chew speaks to Biwa Kwan about campaign Project 18c.
She says between 20 and 30 councils, including Fremantle in Western Australia and Darwin in the Northern Territory, are considering the motion.
Labor councillor James Shaw from the Parramatta City Council in western Sydney says councillors voted by a narrow margin to support the motion on Monday night.
"These changes impact on our community, more so than many others because we've got such a diverse community, a diverse group of people from ethnic backgrounds," he said.
"(And) also because we're part of a coalition of councils who oppose these changes, and (we're) also part of a coalition with a whole range of community groups.
"It's important that the federal parliament leads by example here and says that it is wrong for people to be making comments which are offensive on their basis of their race. And if they watered down these laws, I think that sends a very bad message to our community."
