Mid-morning traffic is tipped to be the worst time to travel these holidays, but heavy traffic will ease in most places by mid-afternoon.
There isn't any significant congestion throughout the country today, except for traffic heading northbound on State Highway 1 near Puhoi.
While traffic is expected to be bad on the border of most main centres, horrendous traffic is expected throughout Kāpiti Coast.
Each year an average of 11 people are killed and 400 injured on New Zealand roads during the Christmas-New Year holiday break.
The holiday road toll is at four: Two people died after a crash in southeast Auckland on Christmas Day and two others in a crash in Henderson this morning.
Traffic heading north from Auckland eased over Christmas Eve and Christmas Day, but will pick up again today.
Heading south from the City of Sails, traffic congestion is forecast to be at its worst from tomorrow to December 30.
In the Kāpiti area, traffic heading north between Peka Peka and Otaki on State Highway 1 is expected to be slow-moving from about 8am and 1pm. For those heading south, traffic would be at its worst in the afternoon from 1pm onwards.
To help combat the amount of time stuck in traffic, Waka Kotahi has developed an interactive map highlighting the worst times, days and locations to be on the move. (Scroll to the bottom of this story for the interactive).
Waka Kotahi NZ Transport Agency general manager safety, health and environment Greg Lazzaro said this was a special time of year, and he didn't want anyone's holiday to be marred by an avoidable tragedy on the roads.
"We're coming to the end of what has been a long and difficult year for many, and we all deserve a safe and relaxing holiday," Lazzaro said.
"Deaths and serious injuries on our roads are not inevitable, and we shouldn't accept that serious crashes are just another part of the holidays."
National road policing manager Acting Superintendent Gini Welch said with more cars on the road, there was naturally more risk, so it's more important than ever that people are focused when they're driving so that everybody can arrive alive.
"We all need to do the simple things to keep safe on the road. That means watching your following distance and keeping your speed down," Welch said.
"It also means resting before you set off on your journey, and sharing the driving if you can."
NZTA's top tips for 'driving safely, arriving alive':
• Check your car is in good "health" before you head off: Check your tyre pressure and tread, windscreen wipers, indicators and lights.
• Take extra care when travelling in holiday periods because of increased traffic volumes, congestion, tiredness and people driving in unfamiliar environments.
• Drive to the conditions: whether it's the weather, the road you're on, the time of day or amount of traffic.
• Avoid fatigue: Take regular breaks to stay alert.
• Keep a safe following distance from vehicles in front so you can stop safely.
• Be patient: overtaking is unlikely to make a significant difference to your journey time because of the amount of traffic expected over the weekend.
• Allow plenty of time: Remember you are on holiday, so there's no need to rush.