Wanaka motel owner Peter Sutherland confirmed yesterday he had made the complaint in respect of Mr Boult's part in the debate over a visitor levy while being chairman of tourism group Wayfare.
However, Mr Boult put the complaint down to an electioneering tactic.
The council has suggested to Government a 5% levy, or bed tax, on accommodation providers to help fund infrastructure.
Wayfare owns Cardrona Alpine Resort skifield and other tourism activities which Mr Sutherland believes should be included in a broader-based levy.
Mr Sutherland said it was "absolutely clear'' in the council's code of conduct how conflicts of interest should be dealt with.
"It's regarding his failure to declare his conflict of interest being chairman of the Wayfare Group and promoting a visitor levy which excludes his own company.''
He could find no record in council minutes over the last seven months of Mr Boult declaring a conflict of interest, but other councillors had declared conflicts of interest over various matters, and taken no part in discussion or voting.
Last month council candidate Niki Gladding laid a complaint against Mr Boult, alleging he has "failed to manage'' his conflicts of interest in respect of the proposed visitor levy and proposed airport development.
But the mayor questioned the timing of the complaint.
"My interest in Wayfare/Real Journeys was declared in 2016, and remains as a non-shareholding director. I earn a minority of my income from that.
"If I am considered by Mr Sutherland to have a conflict, then so do practically all the other elected members who earn an income in the district.
"If the levy were to be taken further than accommodation, it would have to include all commercial activities - why would you include tourist activities and not tourist retailers, and if you include them, then you must include gas stations, supermarkets, bars, and restaurants.''
He confirmed the issue had been referred to a Council-appointed lawyer who deals with complaints of this nature.
"As a result, I should not comment further other than to say that many elected members and candidates will have some conflicts they need to manage, and I am very comfortable with how I have managed my actions. I am sure the investigation will support that.''
Auckland lawyer Mike Holm, chairman of the council's elected member conduct committee, is investigating Ms Gladding's complaint.
