A 16-year-old volunteer was able to purchase alcohol at four of fourteen businesses visited during a controlled purchase operation by police in Masterton, Featherston, Greytown and Carterton last month.
The four licensed Wairarapa premises will face the Alcohol Regulatory and Licensing Authority.
They may face fines and could have their licenses temporarily suspended.
Sergeant Shane Benge, of the Police Alcohol Harm Prevention office said the result of the operation was "disappointing".
"Licensed premises have a 'no ID no service' policy for anyone who looks under the age of 25. As our volunteer did not have any identification with them, these sales should not have occurred.