"I think it's probably conflicting demands for expenses this time of year and people distracted with the holidays."
When asked by police, most drivers said they had forgotten, he said.
Most of the drivers were issued with a $100 fine and 15 demerit points but qualified to have the ticket withdrawn if they renewed their registration within 14 days.
More than 10 tickets were issued at the two checkpoints and although exact numbers were not available, most were issued for lapsed registrations, Mr Osland said.
Police would be continuing to run checkpoints throughout the summer.
"People are on holiday and people drink through the night and with the lower alcohol limits people can still be over the limit at 9am in the morning -- and then there are the people having lunches and things."