"We'd ask people to have those hard conversations with people - their work colleagues and friends - before they kill somebody or themselves."
Those getting caught were the "tip of the iceberg", and police were putting more resources into the problem, Gill said.
Four people were caught drink-driving on Sunday. A Queenstown man recorded 400mcg after being stopped on Gorge Rd at 1am. About three hours later, another local man blew 590mcg after being stopped on Stanley St.
At 4.15am, a 20-year-old Christchurch man recorded 448mcg after hitting a parked vehicle on Fernhill Rd.
He was charged with drink-driving, careless driving, possession of cannabis and possession of a cannabis utensil.
At 11.20pm a Queenstown man recorded 1008mcg after being stopped on Fernhill Rd. On Saturday, a 53-year-old woman blew 862mcg at a random stop on McBride St, Frankton.