"It will depend upon the circumstances and our officers have always had discretion."
Mr Bush said drivers often set their cruise control to what they believed the tolerance was, for example 110 km/h. He advised drivers to set their cruise control to the limit, or just below, as any speed above the posted limit would warrant an infringement.
The zero tolerance could be a permanent part of road policing, Mr Bush said.
"We'll assess that at the end of the campaign, but I can't see us changing our approach on that."
Although police would not be following a 4km/h tolerance this summer, speed cameras will have a threshold of 4km/h during December and January.
Last year's Safer Summer campaign introduced a speed tolerance of 4km/h above the speed limit for all of December and January, rather than just over the Christmas and New Year period. Police reported a 36 per cent decrease in drivers exceeding the speed limit by 1-10km/h and a 45 per cent decrease for speeding in excess of 10km/h.
Fatal crashes decreased by 22 per cent over the summer campaign. Serious injury crashes decreased by 8 per cent.
Minister of Police Michael Woodhouse said while Mr Bush hadn't confirmed that the zero tolerance would be made permanent, it has been effective over holiday weekends.
He said he didn't have any concerns around how it would be enforced. "I'm sure the police will take a sensible approach to enforcement."
He believed New Zealand could soon be realistic in setting a goal of zero road deaths.
ACC Manager of Motorist Injury Insurance Paul Gimblett said during the summer period of 2012-13, ACC received around 85 road injury claims a day.
"That's why we're urging all Kiwis to stick to a safe speed and drive to the conditions."
National director of road safety charity Brake, Caroline Perry, said she supported the Reach the Beach campaign.
The campaign begins on Monday, the same day the new alcohol limit comes into effect. The legal limit for drivers over 20 will be dropped to 250 mcg of alcohol per litre of breath.
Q&A
What are the messages in the 'Reach the Beach' campaign?
Police will have no tolerance for drivers exceeding the speed limit. Every driver who is above the limit will be stopped and breath-tested.
When does the campaign run?
From Monday, December 1, for at least two months.
Will I get a ticket if I am driving 52km/h in a 50km/h zone?
It depends on the discretion of the police officer who pulls you over.
What about speed cameras?
Speed cameras will be set for a 4km/h tolerance.