The man was a passenger in car that collided with a truck at the corner of Horseshoe Bush Rd and Dairy Flat Highway about 4:30pm on Friday afternoon.
Rodney Area Commander Inspector Mark Fergus said it appeared that the car crossed the centre line in to the path of the oncoming truck.
The teenage driver of the car was transported to North Shore Hospital with minor injuries and the truck driver came away unscathed, Mr Fergus said.
Brett Gliddon, highway manager for New Zealand Transport Agency (NZTA), said traffic volumes north and south of Auckland would increase tomorrow morning and peak in the afternoon.
"We anticipate around 3000 more vehicles than normal will be using the toll road north of Auckland," Mr Gliddon said.
"Drivers are more likely to face delays and queues on rural sections of the state highway network where there isn't the same room as Auckland's motorways to handle high volumes of holiday traffic."
For people driving between Northland and Auckland, Mr Gliddon said rural State Highway 16 between Auckland and Wellsford was a less congested alternative route to State Highway 1.
In the Wellington region, the Agency will close the State Highway 1 southbound passing lane north of Otaki tomorrow from around 10am until about 8pm.
The agency said congestion would be monitored through Otaki, and temporary traffic management measures put in place to improve traffic flows if needed.
Other busy roads this time last year were State Highway 1 in north Waikato at Taupiri, and State Highway 2 in north Waikato between Kopu and Pokeno.
Unsettled weather was expected in many regions tomorrow, and Mr Gliddon said it would be important to drive to the conditions.
"Reduce driving speeds below the legal limit and increase following distances," Mr Gliddon said. "Vehicles need two to three times more stopping distance in wet weather.
One person was killed on the roads last Labour Day weekend, 2013, police said.
This was the lowest number of road deaths recorded over a Labour Day weekend since records began.
There were, however, 83 reported injury crashes which left 20 other people with serious injuries, police said.
