A lawyer specialising in privacy matters has warned that a national database of mobile phone owners would be another step in the surveillance society and would not work.
Police want owners of pay-as-you-go handsets to be registered, saying their investigations are impeded by a lack of access to details on users of such phones.
However, lawyer John Edwards says such schemes penalise the majority of law-abiding people by imposing extra costs and curtailing their privacy.
Mr Edwards warns that criminals would sidestep a mobile phone register by using stolen handsets, adding that police need a better justification for such a scheme to receive serious consideration.
In Australia, buyers must present identification such as a passport to the retailer.
The officer in charge of the metro crime unit in Wellington, Detective Senior Sergeant Darrin Thomson, says investigations are slowed by lack of access to phone owners' details.
Mr Thomson says a mobile phone register would be similar to the White Pages.