A reminder from Hamilton's mayor to watch your mouth has left a city councillor apologising for using homophobic slurs.

Councillor Garry Mallett using derogatory terms towards gay people in a meeting last week while describing pink paper, and again when questioned about his language by another councillor.

Mr Mallett was originally unapologetic and saying there was no reason for him not to use the terms and telling the public to get over it but has since backtracked and apologised.

Hamilton mayor Andrew King said he did not condone Mr Mallett's comments.

He said he will remind councillors to behave respectfully.

"Following my discussions with councillor Mallet and his apology to those, I consider the matter closed."

King said he didn't hear the comments at the time but doesn't support them.

He said they are a welcoming and diverse city and he will remind his councillors of that.

"This diversity has to be treated and respected and I will be reinforcing this message to our council."