Police in Palmerston North say two bars in the city sold alcohol to minors on Saturday night.
Teenage volunteers attempted to purchase alcohol from 29 licensed premises, as part of a nation-wide blitz on alcohol and crime.
Police said two bars made sales to them and one of the premises dispensed alcohol to the minors on two occasions in the space of two hours.
Sergeant Glenn Ryan said one bar completely failed to monitor the intoxication levels of its patrons, many of whom required assistance walking. Others lost their balance and fell over in the streets.