Police warn they will be proactive in cracking down on newly banned drugs under a law which came into effect at midnight.
The Psychoactive Substances Act bans sales of synthetic drugs from dairies, grocery stores, petrol stations or anywhere alcohol is sold.
The law also prohibits sales to people aged under 18, introduces strict labelling requirements, and bans advertising, except for at the point of sale.
Synthetic drugs must now be approved by an official regulator within the Ministry of Health before they can go on sale.
Deputy Commissioner Mike Bush said police would be proactive in clearing communities of the substances.