A person has died after a serious crash near Warkworth, which closed State Highway 1 in both directions.
The person was trapped for 40 minutes in a vehicle after the incident, 5km south of Warkworth, this afternoon.
SH1 was closed in both directions between Woodcocks Rd and Puhoi Rd. The road was also closed at Silverdale but diversions are in place.
Emergency services were called to the scene just after 3pm, where a southbound vehicle and a northbound vehicle collided, according to Waitemata Police.
Another person was seriously injuried and two others were moderately injured.
The incident, in Omanaia, west of Kaikohe, happened just before 10pm last night.
Two men aged in their 50s were leaving a house on State Highway 12 when they went to cross a ford which usually allowed access across a creek between the house and road.
Serious crash investigator Senior Constable Warren Bunn said as the men went to cross the ford, their van was swept more than 100 metres downstream.
The driver managed to escape the vehicle with minor injuries. The passenger, from Omanaia, was found dead on the bank a short way from the van.
"The ford itself is easily passable but with the heavy rain, the van has entered it and been swept away," Mr Bunn said.
Volunteer fire crews from Rawene were also at the scene with the station's chief fire officer Dave Williams describing the downstream current as "pretty fierce" following heavy rain.
Mr Williams said he knew the deceased, "a really really nice guy". "We're a small community, so [knowing the victim] is something we deal with regularly," Mr Williams said.
Mr Bunn said it was not yet clear whether the death would be classed as a fatal car crash or a drowning. If it was included it would take the region's toll to 24. This compared to 2015's 23 road deaths in the region.
In another crash in Northland, a 19-year-old man died at the scene after a vehicle he was a passenger in left State Highway 1 and hit a tree, near Towai just after midnight.
The ute was driven by a 21-year-old who lost control of the southbound vehicle as it rounded a corner, Mr Bunn said.
The ute hit a tree and ricocheted about five metres down a bank, landing on its roof. The driver was able to free himself and flag down a passing car, Mr Bunn said.
He was transported to Kawakawa Hospital in a serious condition.
Kaumatua have blessed the sites of both crashes, and the Serious Crash Unit continues to investigate the cause of each incident.
Northland Duty Inspector Riki Whiu said: "Our condolences and thoughts go out to the local families of those who have died in these tragic incidents.
"Any death on our roads is a tragedy, and it's especially difficult for all of our staff to have two fatal crashes in the space of one night.
"Police wish to remind those travelling on our roads, in particular in such terrible driving conditions, to drive to the conditions and look after each other."
This morning a woman escaped with minor injuries after crashing into a building in Onehunga, Auckland.
A driver suffered minor injuries this morning when a car crashed into a barrier on Auckland's North Western motorway.
And a woman also suffered minor injuries when her car went 10m down a bank in east Auckland tonight.The car had left the road on Whitford Rd, by Shamrock Park in the suburb of Somerville, fire services said.
Animals injured
Several animals were also injured in a crash at Tangiteroria on Friday just after 9pm.
Northern fire communications shift manager Jaron Phillips said a crew from Dargaville arrived to find up to 30 cows and a pig loose on State Highway 14 near Paradise Rd.
A car had crashed into several cows, killing one and breaking the legs of two others. The car then caught fire, though its occupants had already got out of the vehicle. The matter had been referred to animal control.
National manager road policing Superintendent Steve Greally said any death or injury on the roads was "one too many".
"Everyone - including road users - need to do their part to reduce deaths and injuries on our roads and in our communities right across NZ.
"Police cannot do it alone. Road safety is everyone's responsibility.
"Education and Police enforcement is just one aspect of keeping the roads safe. The driver and the decisions they make are also an important part of the picture.
"Making smart decisions on the road can be done by following the basic road safety rules."
He reminded drivers to check their speed, drive to the conditions, avoid alcohol, take rest breaks and always wear seatbelts.
He said: "Not all roads are created equal - many of New Zealand's roads are unforgiving and leave no room for mistakes.
"Many of our rural roads are not five star roads and our bodies are fragile. The speed limit is the maximum speed you can travel at safely in ideal conditions. Often a strip of paint is all that separates you from oncoming traffic.
"If you crash - regardless of the cause or who is at fault - speed is the single factor that most affects the outcome. Just a few kilometres per hour can be the difference between avoiding a collision - or a crash with a tragic outcome."