Dunedin's mayor has apologised for questioning a ratepayer's intelligence during a heated and nasty exchange at the council's meeting this afternoon.

Photo: RNZ / Rebekah Parsons-King

Stu Debenham got up to speak, ostensibly about health and safety, during the public forum at the Dunedin City Council's meeting.

However, he instead launched a tirade against mayor Dave Cull.

Mr Cull warned the man twice before councillor Kate Wilson attempted to interject with a point of order.

A clearly exasperated Mr Cull then shouted the man down as he attempted to continue raising issues about the amount of time the mayor spent out of the city, his pay and his role with Local Government New Zealand.

"Mr Debenham, can you just hold for a minute, I'm taking a point of order," Mr Cull said.

However, the speaker continued.

"Mr Debenham, are you deaf or just stupid? Now please wait," Mr Cull said.

The remark drew a shocked gasp from the public gallery at the council chambers, but did have the desired effect as Mr Debenham finally stopped speaking to allow the point of order to proceed.

After matters of administration were dealt with Mr Debenham gave it one more shot, this time turning his attention to his view of the city's inefficiencies.

However, his remarks soon deteriorated into a personalised attack against the mayor again.

Mr Cull cut him off, apologised for his earlier remark and told him his presentation was over as he was being offensive and disrespectful.