A New Zealand library has installed a controversial device that emits a high-pitched buzzing noise similar to a mosquito to discourage youths from loitering outside.

The device – which cost over NZ$1,000 – has been operating day and night to deter congregations of young people around the public library in Christchurch after altercations with customers.



Sometimes called a “mosquito”, it makes a high-frequency pulsing sound that can be heard within a 15-metre radius.

In the past the devices have led to complaints, with politicians in the UK calling for a ban, saying they are discriminatory towards young people, discourage group gatherings and may be harmful to hearing.

The device is marketed as the “ultrasonic teenage deterrent” but the whine apparently can be heard by people under the age of 25, who usually have more acute hearing than older adults.

Carolyn Robertson, Christchurch council’s head of libraries, said the Papanui Library where the device was installed had been having trouble with youths and the council was forced to act.

“Customers had complained to library staff about such issues as swearing, abuse, standover tactics and intimidating behaviour,” Robertson said.

“Customers said they didn’t feel comfortable using library services due to this behaviour.”

Christchurch city council said the device had recently been switched off while it investigated its use.

Since the device had been put in, customers had reported they felt safer entering the library. But local schools said the annoying and unpleasant sound could be discouraging children from using the facility.

“I find it very strange they have decided to use this device during opening hours when really we all need be encouraging children to read,” said a local children’s librarian.

“It is not a very good idea at all. Any repellant sound is going to be a barrier to children wanting to visit the library, but especially for children with autism or Down’s syndrome who can be especially sensitive to noise.”

Shirley-Papanui councillor Pauline Cotter told Radio New Zealand the targeted nature of the device could be a human rights issue.

“I don’t like the fact that we are producing this high-pitched noise that apparently only they [young people] can hear it, but it’s a very horrible sound and I wonder if even it’s breaching a human rights issue actually,” she said.



“There must be a better way.”