Canterbury police say they issued more than 100 tickets to motorists for crossing the centre line on State Highway 1 during the long weekend.
A police operation focused on winding stretches of road along the highway near Kaikoura.
Senior Sergeant Phil Newton says most of the motorists were going too quickly into bends, and would drift into the opposite lane in the hope that nothing was coming towards them.
Mr Newton says that's extremely dangerous driving and puts others at serious risk.
Each offending driver was fined $150 and received 20 demerit points.
A similar operation the same time last year, targeting the same behaviour, also resulted in about 100 fines.