A nationwide police blitz next week will target motorists who flout the cellphone ban while driving.

Police say they will be out in force during the campaign, which aims to remind drivers about the law change three years ago.

Drivers who ignore the ban face an $80 fine and 20 demerit points.

The law allows drivers to use hands-free mobile phones, but they must be completely voice-activated unless they are securely mounted, in which case the driver can operate them infrequently and briefly.

Drivers who do not have hands-free phones have to pull over to make, receive or end calls.

Reading, writing and sending text messages is banned under all circumstances while driving.

Police recommend drivers switch off their phones while driving to minimise distraction.

The blitz will start on Monday and wrap up on Sunday, December 2.

Police will also be checking to make sure all car occupants are wearing seatbelts.

- APNZ