More than a quarter of drug offences detected in the Whanganui region never go to court.
Statistics revealed by police show 60 of the 213 drug offences in the region last year resulted in warnings - with 30 of these informal warnings.
A Whanganui lawyer, who didn't wish to be named, said the use of warnings was a good policy for both offenders and the justice system.
"For people that haven't had any history with the police system, often that's enough to steer them away - a short, sharp shock," he said.
"The courts are busy dealing with higher-level offenders, and punishment levels at the lower end are relatively small. It just puts strain on the court system."
Drug Foundation executive director Ross Bell said fewer convictions for low-level drug offences is the right direction but the Government needs to make clearer policy changes into law.
"It's good police are shifting their priorities on to more important things, but what that means is the Government is being irresponsible. It's letting the police do what should be done through policy and enforcement practices, rather than it become a government policy and ultimately a change in the law."
Police introduced a formal pre-charge warning aiming to reduce the number of low-level offences going through court. A pre-charge warning results in an offender being processed at a police station, but the warning does not appear on a criminal record.
In a statement, police spokesman Tim Anderson said: "Our officers have discretion to warn for offences and police deal with these on a case-by-case basis. In terms of an arrest, every case is judged on its merits and sometimes an arrest is made to enable that individual to get some treatment for the drug problem they may have at the time."