"We're catching more and more people and quite frankly I want to be catching less people, because people heed the message and don't go round driving at their cellphones.
"What's quite clear is people aren't getting the message and that's being reflected in the fact that we're just catching ever-increasing numbers."
Mr Griffiths said that for most motorists it was a daily occurrence to see other drivers on the phone.
"It's quite frightening when you think about it - the car coming towards you the other way could have somebody on their cellphone paying very little attention."
Cellphone use was a factor in many crashes but was under-reported because it was difficult to detect.
Police would be out in force during the week-long campaign, which starts on Monday and wraps up the following Sunday.
Mr Griffiths said the campaign was not a one-off, but part of an ongoing effort to tackle the problem.
"It's really a chance to lift the public profile."
Police statistics show Auckland had the greatest number of drivers flouting the ban in the first two years - but the city has now been edged out by Canterbury.
Officers issued 2521 infringement notices in the Canterbury police district in the year to October - a big increase on 1682 the previous year and 1101 in the first year of the ban.
In the Auckland police district, there were 2157 infringements in the last year, up on 2156 the previous year and 1850 in the first year.
Waitemata had 2157 infringements in the last year, up on 1749 the previous year, while Counties-Manukau had 1054 infringements, up on 920.
No other districts topped more than 1000 infringements in any year.
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.
Police will also use to next week's blitz to check that all car occupants are wearing seatbelts.