Alongside controlled purchase operations, police used tools and initiatives including foot patrols, licensed premise checks, and working with local community groups, councils, businesses, and agencies to prevent alcohol harm.
The changes to the Sale and Supply of Alcohol Act 2012 and the lowering of drink-driving limits had also had a positive impact on reducing alcohol related offending, Mr Thomson said.
Controlled purchase operations were used in conjunction with licence compliance checks, and were an effective tool in ensuring licensed premises and certified managers were operating within legislative requirements, he said.
During the operations carried out in 2013 in Wanganui, two licensed premises failed as a result of selling alcohol to a minor.
Those breaches were referred to the Alcohol Regulatory and Licensing Authority for the appropriate action.
Since those breaches, Wanganui police had been working with licensed premises and partner agencies to further educate and inform businesses about their legislative requirements, and training packages and seminars had proven to be effective, said Mr Thomson.
"While we saw no business fail a controlled purchase operation in 2014 in Wanganui, alcohol-harm reduction continues to be a priority for police including the sale of alcohol to minors."
Wanganui District Councillor Philippa Baker-Hogan said she was surprised at such a drop in the number of controlled purchase operations in the area between 2013 and 2014.
"I haven't received anything to tell me that we should take our finger off the pulse on this issue. It just seems a significant reduction."
Ms Baker-Hogan, who is also on the Whanganui District Health Board, said the purchase and use of alcohol was an issue in the area. However, she agreed that controlled purchase operations were just one tool in a broader toolkit for addressing youth drinking.
The reduction in controlled purchase operations raised questions around police and council resources, she said.
The council had not finalised its Local Alcohol Policy which would allow the community to have more say about the sale and supply of alcohol.
Ms Baker-Hogan said she was concerned about how long it was taking to develop the policy but the council had been advised to take its time getting the policy right, rather than ending up in litigation with the alcohol industry.
According to police figures, there were no prosecutions in relation to the sales to minors in Wanganui and Marton areas in 2013. Four people were dealt with by the licensing authority without going to court.
National co-ordinator alcohol harm reduction, Senior Sergeant Andrew Smith, said a case would go to court if someone did not have a licence or management certificate because they could not be dealt with by the licensing authority.
Prosecution and licensing authority numbers could be higher than sales numbers because more than one person might be involved in a sale.