Constable Nick Turner, of Dunedin, said a team set up the checkpoint on State Highway 88 about 4.20pm.
In about an hour officers breath-tested 18 drivers who either admitted consuming alcohol or failed an initial screening test.
The high number of drivers who had been drinking was concerning, because there was evidence that every drink contributed to danger on the roads, Const Turner said.
‘‘The consensus is that [alcohol] is impairing."
A 50-year-old woman recorded a breath-alcohol reading of 580mcg and was discovered to have been driving while disqualified.
The legal limit for an adult aged 20 and over is 250 micrograms (mcg) of alcohol per litre of breath.
The woman's car was impounded and she was due to appear in court.
Const Turner said it was also alarming that two people were found without their seatbelts on, and frustrating that the simple message of ‘‘make it click’’ did not seem to be getting through.
