Auckland police say some of the city's alcohol retailers are ignoring their responsibilities by supplying minors.
An operation at the weekend targeting parts of the inner city, including the suburbs of Mt Eden and Port Chevalier, found five retailers out of seven supplying minors.
In some cases a teenager even showed identification stating they were only 16.
Police said the result was unacceptable and concerning, and suggested there was a long way to go before liquor licence holders fully understood their obligations.
Each of the five sites will be prosecuted, with the Alcohol Regulatory Licensing Authority determining the final outcome.