The substances used to make illegal drugs such as methamphetamine is the focus of a police conference beginning in Wellington on Tuesday.
The New Zealand Police is hosting the National Chemical Diversion Congress, which is usually held in Australia.
In October, Customs New Zealand intercepted about 100kg of the cold medicine Contac NT which was concealed in furniture - enough to make $28 million worth of methamphetamine, also known as "P".
The National Drug Intelligence Bureau says the amount of Contac NT that gangs import from China is one of the biggest illegal drug problems facing New Zealand.
The agency's coordinator, Detective Inspector Stuart Mills, says holding the conference in New Zealand will give police the opportunity to learn more about preventing the manufacture of drugs such as "P".
Key subjects include an Australian programme that tracks pharmacy sales of medicines used to make methamphetamine.