Police road policing data shows last year police caught 2273 people using cellphones while driving.
The figure is the highest recorded in the district since cellphone use while driving became an offence in 2009.
Southern district road policing manager Inspector James Ure, of Dunedin, said offending against mobile phone rules seemed to be systemic across all age groups.
Although he could not give exact numbers, investigations had made it clear cellphone use had contributed to some serious crashes.
The Dunedin road policing team would be working with the Dunedin City Council this month to target drivers using their cellphones.
The team was running checkpoints at all hours, Insp Ure said.
As Easter approached, drivers could expect an increase in road policing checkpoints across the Southern region.
The penalty for using a hand-held cellphone while driving is $150 and 20 demerit points.
