Ms Bonham confirmed yesterday she faced investigation.
The nature of the inquiry has not been made public, but it is listed under the "closed meeting" part of the agenda for tomorrow's full Central Otago District Council meeting, which says the public will be excluded while that item is discussed, to protect privacy.
The resolution had been made under the Local Government Official Information and Meetings Act 1987, the agenda said.
Central Otago Mayor Tim Cadogan and deputy mayor Neil Gillespie were asked for comment about the item but said they could not confirm the identity of the person being investigated or details of the case, as it was not permitted under the code of conduct process.
Mr Cadogan said it was vital to protect "the integrity" of the process, and Mr Gillespie said it was "important that it goes through proper process".
The Otago Daily Times then started contacting councillors as listed in alphabetical order on the council's website. Ms Bonham is the first person listed, and said she was the person facing the code of conduct investigation.
She initially said she would provide further comment about the matter, but then did not respond to messages.
Ms Bonham is a first-term councillor, representing the Earnscleugh/Manuherikia ward.
