Police are being criticised for conductinga trial that allowed officers to be lenient on offences such as cannabis possession.
A drugs consultant says it undermines laws designed to clamp down on gangs and the methamphetamine trade, which come into effect on Tuesday.
Mike Sabin says the three-month trial on Auckland's North Shore gave officers the discretion to let people off with a warning for crimes carrying a jail term of less than six months.
Mr Sabin says the policy will be extended in the region and to offences carrying a jail term of two years or less.
He says that means people will not be held accountable for offences such as cannabis possession.
Mr Sabin says fostering demand among drug users will undermine attempts to get tough on suppliers.