Devices that block cellphone calls and GPS signals are being sold illegally on the internet in New Zealand internet sites.
The jamming devices had sold for as little as $99 on Trade Me and Sella, the Herald on Sunday reported.
The newspaper said the devices could not be used in New Zealand without a licence and selling or manufacturing them was banned. Some versions could interfere with aircraft navigation and police communications and some American experts said they could bring down a plane.
Only the Corrections Department may use mobile phone jammers and only within prisons, the newspaper said.
The Ministry of Economic Development said the jammers could stop people making emergency calls and about one a week was removed from sale on the internet. Sellers or users face a fine of up to $1250.
NZPA