A high-pitched noise used by Christchurch City Council to deter young people from loitering and fighting outside Papanui Library has been turned off.
The "mosquito" device emits a noise that is undetectable by adults but is uncomfortable for people under 25.
It had been used in the library foyer during the night, but the council recently moved to keep it on during the day as well.
Shirley-Papanui ward councillor Pauline Cotter said this week the device was the wrong approach to dealing with the problem.
She said she wondered if it might be in breach of human rights.
The council said today it would further investigate and evaluate its use.