Dunedin Mayor Jules Radich and councillor Carmen Houlahan breached the council's code of conduct, an independent investigator has found.
The investigation was launched after then-deputy mayor Sophie Barker resigned from the position and laid a complaint against Radich for what she characterised as a breach of a confidential council meeting by the mayor when speaking to RNZ.
It followed the council censuring Strath Taieri Community Board chairperson Barry Williams in August for a racist outburst and asking for him to resign from the role.
That letter was sent to media, along with a statement which said no further comment would be made by the council.
During a subsequent interview, Radich told RNZ that the racist outburst had occurred in a pub and was "a relatively minor thing".
As a result, Barker - who remained on as a councillor - and senior councillor Jim O'Malley filed a code of conduct complaint against the mayor in September.
In her letter of resignation, Barker said it would be difficult to maintain a working relationship with the mayor, especially after her complaint.
In response to the pair's complaints, Houlahan sent Barker 17 text messages and called eight times.
The attempts to make contact occurred over two days.
Houlahan also rang O'Malley 12 times.
Barker then also laid a complaint against Houlahan.
She told RNZ at the time the contents of the messages were upsetting.
Independent investigator Jordon Boyle found Radich and Houlahan had materially breached the code of conduct and brought both into disrepute.
In respect to Radich's breach, Boyle also found it brought the council into disrepute.
At a behind-closed-doors meeting on Tuesday, the council voted to endorse Boyle's findings and ask Houlahan to write an appropriate letter of apology to Barker.
Radich had already publicly apologised for his comments.
All councillors voted in favour of the motions with the exception of Lee Vandervis, who had himself previously been found to have breached the code of conduct.
Reports reveal content of messages to deputy
The council had also released partially redacted reports related to the two breaches.
The report also revealed the contents of Houlahan's text messages.
Upon learning of Barker's code of conduct complaint against the mayor on 8 September, Houlahan called eight times and sent six text messages in quick succession, starting with: "This has to be wrong. Is this you taking this code of conduct? I have just said it can't be you are not this nasty. You need to get a correct. People will stoop to some pretty low shit but this is very low to say you have done this. This is awful. I'm happy to say you wouldn't be this nasty. No one with a right mind would do this! Good grief. It is unbelievable!"
Barker responded to Houlahan after the first six messages, telling her it was not personal and the complaint only considered whether the code was breached.
"No it can't be true. Sophie you are better than this. Why would you divide council?" Houlahan responded.
"Jules has apologised and he has only been nice to you. You are his deputy. Why would you turn on him?" Her second message in response read.
Houlahan then again started messaging Barker the following afternoon: "I've had numerous people talk to me about this and they all say the same thing. Dirty politics!!!!!"
"Please understand that it's very likely the Code of conduct was broken. This needs to be investigated," Barker responded.
"Jules apologised the minute he realised he stuffed up. This move by you was nasty. To say I am shocked and disappointed is just the start." Houlahan fired back.
Barker then told Houlahan she did not know the full story.
"What is the full story then," Houlahan asked.
"Sophie I have been one of your biggest champions. I rave about you but I see nothing positive about this and the way it was done is planned, cold, calculated and nasty. You said nothing to Jules and we were all in a meeting together. You can do better than this Sophie. You are better than this! Women can be successful without lowering their standards.
"You will have a good chance at Mayor next time you don't need to put the boot into Jules."
Investigator finds councillor's actions 'unacceptable'
Boyle said Houlahan's actions were "unacceptable, particularly in a professional environment".
"Cr Houlahan maintained the view that her messages were almost entirely polite and many highly respectful. Cr Houlahan considered any negative comments were about the process, not Cr Barker," Boyle's report said.
"I disagree. This cannot be reconciled on the evidence before me. Saying someone cannot be trusted, they have acted in a cold, calculated and nasty way, implying they are stupid ... is not polite or courteous."
Boyle also found Radich's comments to RNZ ultimately led to the person who was subjected to the racist outburst by Williams being identified.
"It is important for people who engage in processes like this to have confidence their information will be kept confidential, particularly when they could face negative consequences if this confidence is breached.
"I consider failure to keep this information confidential could bring Mayor Radich and DCC into disrepute and undermine the public's confidence in DCC."