Police have named the man killed after his car rolled near Mangatarata yesterday morning.
He was Edward Malcolm Paul, 35, of Mangere.
Sergeant Jim Corbett said Mr Paul had been travelling to Coromonadel Town to spend Christmas with his family, when his car rolled on to its roof on SH2 at Mangatarata, 1km west of the SH25 intersection in the Hauraki district
Mr Corbett said the 4.30am crash could have been caused by a combination of fatigue and speed.
The state highway was closed while firefighters cut Mr Paul from the wreck. The Westpac rescue helicopter was dispatched but he died at the scene before it arrived.
The death was one of two on the roads on Christmas Day.
An 80-year-old man is believed to have had a heart attack just moments before he lost control of his car and crashed in front of an off-duty police officer yesterday afternoon.
The man was travelling north with his partner of three years when he veered off SH1 just south of Warkworth about 12.50pm.
The officer pulled the driver from the car and began CPR.
Ambulance officers took over from him but the octogenarian died at the scene.
The man's partner, who was not injured in the accident, was last night being cared for by relatives in Whangaparaoa.
Serious crash unit staff are investigating the Warkworth and Mangatarata accidents.
Further south, bad weather forced police in the lower North Island to urge motorists to take extra care. Inspector Paul Jermy said wind and rain were causing visibility problems, and a diesel spill near the Kaitoke Gardens north of Upper Hutt created an additional hazard for motorists.
One lane of the Hutt motorway was blocked after a south-bound car struck the median barrier.