From Stuff: (the last part of the article; read the link for the full details)
Ministry of Business, Innovation and Employment's Radio Spectrum Management (RSM) compliance manager Fadia Mudafar said it was contacted by Invercargill Police who said there was a significant number of people getting replacement batteries for car remotes because they were not working.
An RSM Compliance Officer provided advice to police on what frequency it was likely to be and a police technician tracked it to a legitimate repeater on top of the Menzies Building.
A search of the radio frequency license register shows amateur radio operator Daniel Erickson holds the licence on behalf of amateurs to transmit on 434.050MHz.
Mudafar said amateurs have primary use of the frequency range 433.050 to 434.920MHz.
"Remote controls, such as those in car door remotes, operate within the Short Range Device Notice and have secondary use of the same frequency range 433.050 to 434.920MHz."
Both parties are legally allowed to transmit on the frequency.
The repeater is currently off while the license holder works with RSM to find a solution, Mudafar said.
"RSM has seen similar issues on shared frequencies before, but not with amateur transmissions."