Holidaymakers will start leaving main centres in droves this afternoon - and police will be watching closely as they try to keep the road toll at its 50-year low.
Last year, 12 people died and almost 400 were injured on roads during the two-week Christmas and New Year holiday break.
Ninety-nine fewer people have died on the roads this year than last year.
"We don't know all the factors behind what is driving the reduction in the road toll, but we do know police visibility and action play an important part," said road policing national manager Superintendent Paula Rose.
Police would be stopping anyone caught driving at more than 4km/h above the speed limit and would be taking drink-drive breath tests at all times of the day, she said.
Although the road toll was better than in previous years, it was still a problem.
"It still means that 269 families will be missing a family member this Christmas," said Ms Rose.
The Transport Agency said it would be putting most roadworks on hold during the holiday period to avoid adding to traffic problems.
But it would take advantage of Auckland's quiet streets to work on the Victoria Park tunnel, the Harbour Bridge and, next month, the Lincoln Rd interchange on the Northwestern Motorway.
Many motorists will be passing through Waikato, where the road toll has defied the national trend and risen.
The agency's state highway manager, Kaye Clark, said delays were possible on the way to Coromandel despite the opening of a two-way Kopu Bridge.
"The important thing is to reach your destination safely," she said.
"Even if it takes a little longer to get there, please be patient, keep your speeds down and take regular breaks on long journeys."
A survey by navigation system maker TomTom suggested as many as 1.7 million New Zealanders would be on the roads over the holidays - and they all planned to leave about the same time tonight and tomorrow morning.
"Most of the drivers we questioned stated that they will set off in the early morning or late at night to try and beat the traffic, but few realise that every other Christmas driver has the same plan," said Asia-Pacific public relations manager Valerie Cross.
Automobile Association motoring affairs general manager Mike Noon said as soon as drivers noticed heavy traffic, they should switch their mindset, relax and go with the flow.
"It's important not to set silly expectations - don't say you'll be there by 1pm, just say you'll get there sometime in the afternoon," Mr Noon said.
"If you arrive early, that's marvellous. If you get held up, that's no problem."