Gwent Police breathalysed over 2,200 drivers over the Christmas period, with 42 found to be over the legal drink drive limit.
Across the country in the All Wales Winter Anti Drink and Drug Driving Campaign 30,700 drivers were tested, with 480 caught drink driving.
Those caught in Gwent rose from 39 the previous year.
Gwent Police Superintendent Mark Warrender said: “Although it is a small percentage of the number of people tested, it is still disappointing that throughout the Christmas period 42 drivers in Gwent considered themselves to be above the law by getting behind the wheel having consumed too much alcohol.
“We will not tolerate drink driving in Gwent. Our high profile, education and enforcement campaigns will continue this year to highlight the risks and consequences of such irresponsible behaviour, and our officers will be out every day policing the roads to target those who break the law.”