A statement from parent company MediaWorks said: "A comment was made last week by a George FM announcer which was intended as humour. George FM wants to make it clear that the comment was unacceptable and has taken immediate disciplinary action. There will be no further comment on what is now an employment matter."
Kirby, who co-founded the station in the late 1990s, is due to marry Nash next month. He did not return calls.
Meanwhile, an Auckland bar has suspended a bouncer for using a homophobic slur towards a group of men on a stag do.
Neighbourhood Bar in Kingsland took action after the doorman told a group of men on a stag do that they didn't let in "gay c****".
The groom was dressed in pink with fishnet stockings.
Music journalist Duncan Greive, who was among the group, praised Neighbourhood, part of the Mac's Brewbar chain, for taking swift action.