Police used 'violent' sound cannon on Parliament protesters

Police are under fire after using an experimental sound cannon on protesters during the last day of the Parliament occupation.

Documents obtained under the Official Information Act reveal revealed two long-range acoustic devices (LRADs) were deployed on March 6, following a tense standoff between protesters and police during the last day of the 23-day anti-mandate occupation.

The device, which was developed in response to the terrorist attack on the USS Cole, can reach a sound level of 140 decibels, the equivalent of standing directly behind a jet engine.

READ MORE: Mass of debris strewn across Parliament grounds after protest

Anything over 120 decibels potentially causes permanent hearing damage, their use overseas is controversial.

The New York Police Department vowed not to use the device's siren again after being sued for damaging the hearing of multiple people at a Black Lives Matter protest.

Footage obtained by 1News shows protesters blocking their ears, as the police trained the sound cannon on them.

James Parker is the director of a research program on Law, Sound and the International, at the Institute for International Law and the Humanities at Melbourne University.

He said one of the problems with the technology is its indiscriminate nature.

"If you have a truncheon or a gun or pepper spray you can aim it the LRAD you can't really aim you just blast it at a crowd."

Intentionally using loud sounds on a crowd to induce pain, he said, also raises ethical questions.

"The whole point of this deterrent tone is to target the vulnerabilities of human hearing," Parker said.

"It's meant to hurt."

Green Party justice spokesperson Golriz Ghahraman said the use of the experimental technology amounts to police "tyranny".

"We do feel concerned that New Zealand Police are increasingly using experimental methods that are violent, overseas these acoustic missiles have caused permanent hearing loss without a social licence."

When asked by 1News if the use of the device was appropriate considering its potential to cause long-term hearing damage, Police Minister Chris Hipkins said he was unaware of the matter.

"That's an operational issue for the police… I haven't actually been briefed on their action there."

The IPCA received nearly 1900 complaints into the actions of police in response to anti-mandate protests outside Parliament grounds between February and March 2022.

Many of the complaints were from individuals who were not present at the Wellington protest but were "concerned about police actions or inactions".