The Christchurch campaign group Save Our Arts Centre is furious about a suggestion it used illegally obtained information in a court case.
The group and the Arts Centre Trust are battling over a $24.5 million project to house a music school.
The campaign organisation says the director of the city's Arts Centre, Ken Franklin, has implied the group was somehow responsible for, or connected to, the bugging of rooms or hacking into private emails.
Mr Franklin says the group used leaked material in the High Court last year when it tried to stop the project. However he says he has never alleged the group itself hacked into his computer.
A spokesperson for Save our Arts Centre, Dame Ann Hercus, says the group is not responsible for gathering the material.