A large-scale police operation in Nelson has led to 21 drivers being suspended for driving under the influence.
More than 8000 drivers were stopped and breath-tested by police last weekend. Ten drivers will be appearing in the Nelson District Court facing a six-month disqualification from driving.
A further 11 drivers were instantly fined $200 and slapped with 50 demerit points.
All 21 drivers received an immediate roadside suspension.
"If you are in any doubt at all about being safe or legal to drive due to impairment, don't, it's not worth it," said Senior Sergeant Grant Andrews.
He says police are frustrated with people driving impaired and the increase in speeding motorists.
Several drivers have recently been suspended and facing court action for speeding, he said.
"It's doing the basics that will keep you safe this summer.
"Watch your speed and your following distances, stay focused, put your phone out of reach, wear your seat belt, and always drive sober and alert."