People face long delays and massive queues today as holidaymakers empty out of the major centres.

Photo: RNZ / Rob Dixon

Hundreds of thousands of cars will likely hit the road on one of the busiest travel days of the year.

The Transport Agency expects heavy traffic to start early today, making traffic jams likely from midday north and south of Auckland.

State Highway 1 on the Kāpiti Coast north of Wellington is likely to be bumper to bumper from 9am, and from 6.30am tomorrow.

Levin resident Antony Young said he expected massive queues of motorists today, with likely delays of an hour and a half.

"It seems to be getting progressively worse year after year," Young said.

"This stretch of road has overreached its capacity, our infrastructure is crumbling, our national highway system just is inadequate."

He said he feared for locals' safety.

"We're really worried the state highway goes straight through our town. We have young children and a large elderly community that cross that road every day."

Transport Agency Wellington spokesperson Mark Owen said the heavy traffic on the main highways would last well into next week.

"Next Monday [and] Tuesday will be busy, and then ... Christmas Day, Boxing Day and the day after."

"It's really going to be busy from ... Friday right through until the middle of next week."

He said travellers should use a tool on the agency's website to see when traffic would be lightest.

Owen said passing lanes on some of the busier state highways would close to ensure a smoother, safer journey.

He told Morning Report: "Some of the really busier ones, for example when you're heading out of Wellington on State Highway 1, we've closed the passing lane and this is just to try and smooth flows and keep people travelling at a constant speed, and avoid some of the frustration that does occur when you have huge traffic volumes and people trying to merge in and out of the passing lane."

He said the busiest spots would be areas north and south of Auckland, with travellers heading to Northland and Coromandel respectively. Other areas included Tauranga, those heading out of Wellington to the Kapiti Coast, Queenstown and Christchurch.

"All those busy urban areas where a lot of people are heading from the cities to the summer destinations."

Delays could continue throughout summer, with double the usual maintenance road-works planned throughout the country.

Owen said although people would face delays over the summer months - the maintenance work needed to be done, and it was the best time to do it.

He said the work would be paused from today until 6 January to help ease congestion, but there would still be lower speed limits in place where roadworks had begun.

Nine people died on the roads in the official holiday period last year, and 12 the year before.

Police were set to ramp up their presence from today on the roads to popular holiday hotspots, and fixed speed cameras will issue fines to people travelling just 4km/h over the limit from this afternoon though the holiday period.

Acting superintendent Amelia Steel said the summer months were a bloody time on the roads.

"These two months, particularly January, [are when] most people die on New Zealand road so we know that we need to be ultra vigilant."

She had a message to drivers.

"Plan the journey, allow plenty of time ... and just stay focused to ensure that your speed is appropriate for the conditions, to ensure that people are wearing their seatbelts in the car, not to drive while impaired - that's either through drink or drugs or being fatigued."

Steel said the best Christmas present she could get would be for travellers to get to their destinations alive and unharmed.