Mayor Morris Cutforth has admitted firing an obscenity at former councillor and mayoral candidate Vince Cocurullo as tempers flared at the protest at Mander Park.
Mr Cutforth said he regretted saying it, but Mr Cocurullo said he may yet make a formal complaint to the council over the slur.
The pair clashed several times on Saturday as Mr Cutforth defended the council's stance on the trees being removed.
Mr Cocurullo had accused Mr Cutforth of stacking the council's Property Governance Steering Group with rural councillors - Jeroen Jongejans and Greg Martin (Hikurangi ward), Phil Halse (Bream Bay), and Warwick Syers (Whangarei Heads) - ahead of central Whangarei councillors.
As Mr Cutforth walked away from the stoush with Mr Cocurullo he called his rival "a w*****'', which was heard by several protesters.
Mr Cutforth said as soon as the insult popped out he regretted saying it.
"It's not the sort of thing a mayor should be saying and certainly not in front of a whole lot of angry people standing around accusing me of telling lies,'' he said.
- By Mike Dinsdale of The Northern Advocate
