Cr Lee Vandervis is in hot water for allegedly shouting at, standing over and pointing in the face of deputy mayor Christine Garey and behaving so aggressively that she feared he may strike her.
Independent investigator and lawyer Steph Dyhrberg found he behaved "in a manner anyone would have found intimidating" at the end of a council meeting in July and that his breach of the code was "material".
"The behaviour was abusive, aggressive and lacked all courtesy," Ms Dyhrberg said.
The finger pointing was threatening "and made Cr Garey fear Cr Vandervis may strike her".
"The behaviour was highly unprofessional and threatening and affected Cr Garey's perception of her safety in her working environment. It is likely to bring Cr Vandervis and the council into disrepute."
Cr Vandervis did not participate in the investigation. He will have a chance to defend himself at the meeting on Tuesday next week, when councillors will decide if they agree he breached the code and, if so, what sanctions he should face.
Possible penalties include suspension from committees, removal of council-funded privileges, a vote of no confidence or being asked to consider resigning.
Ms Dyhrberg also found an emailed apology by Cr Vandervis was weak and he lacked insight into how he came across.
Councillors Garey, Marie Laufiso and Steve Walker made formal complaints on July 29, the day after the meeting, alleging Cr Vandervis yelled at Cr Garey.
Cr Walker stepped in to protect Cr Garey, the investigation noted.
The incident arose after Cr Garey ruled against Cr Vandervis on a point of order. He confronted her afterwards.
The deputy mayor told Ms Dyhrberg that Cr Vandervis shouted at her and it escalated to yelling.
Cr Garey labelled the behaviour bullying.
She believed she said something like "don't you point your finger at me", because he replied as he walked away, "I'll point my finger at anyone I want".
Though shaken, she said she was not afraid of Cr Vandervis and felt she had to stand up to him.
"I am extremely concerned that this was not a one-off, but a pattern of behaviour which I have observed over several years," she said in her complaint.
Cr Walker said Cr Vandervis was "screaming and yelling". It was an over-the-top "tirade".
Cr Vandervis was "red faced and almost spitting", Cr Walker said in his account.
Cr Walker described the incident as "horrid male aggression".
Cr Laufiso said the faces of Cr Garey and Cr Vandervis were about 20cm apart.
She described the behaviour of Cr Vandervis as bullying and disrespectful.
The Dunedin City Council has kept a file on Cr Vandervis since 2012 and it lists 27 recorded incidents.
They range from claims of swearing and bullying to spraying saliva.
Cr Vandervis rejected the file as "manufactured rubbish".
Cr Vandervis is in his fifth term on the council. He was a close second to Dunedin Mayor Aaron Hawkins in the 2019 mayoralty race.
In his apology, Cr Vandervis said he had not intended to make a scene and he was sorry about his "loudness".
In future, he would make complaints in writing, he said.
On Tuesday, councillors will consider the findings of the investigation, give Cr Vandervis a chance to speak to the council, decide whether the code of conduct has been breached and, if so, whether to impose sanctions.
