In a letter to the Otago Daily Times, a contestant said "following the verdict, discussions with many band members and people in the audience indicated that there was some disbelief at the outcome".
She believed the judges were "biased in favour of the alternative and experimental" and questioned if they were searching for the "Dunedin sound" when they announced Sewage, a three-piece from Logan Park High School, as the regional winner.
She wanted Dunedin judges to "widen their outlook" and acknowledge other genres and talent were deserving of winning an Otago final.
The judges' decision was final, a spokeswoman said.
The judges were Christchurch-based musician Claire Grater, also known as Flip Grater, and a local musician, who preferred to remain anonymous.
He believed the letter was "sour grapes" and said "to completely disrespect the winners is a little naive".
Judging was based on a list of criteria - uniqueness, presentation, energy, communication, tightness, musicianship, vocals, creativity, melody/lyrics and instrumental parts.
Sewage was "very good in their genre" and "really proficient at being different".
The judges "agonised over the decision" and although the music Sewage played was not his "cup of tea" he believed the band was good at what it did.
Sewage drummer and vocalist Gabriel Griffin said the comments in the letter were a "laugh".
He believed whoever wrote it was narrow-minded.
He described the band's sound as "jumpy happy noise rock" and was thrilled to win the regional final.
The national final will be held in Auckland on September 19.
