The spokesperson wanted to thank motorists for their patience following the closure and said an investigating into the crash is ongoing.
A police spokesperson said the male passenger of one of the cars died at the scene.
"Police can now confirm one person has died in a two-vehicle crash in Northland," the spokesperson said.
"The crash occurred on State Highway 1 south of Kawakawa about 4.30pm."
A woman who was driving near the location of the incident at the time told the Herald she didn't see the crash but heard it.
One of the vehicles involved in the crash had overtaken her at speed near Waiomio, she said.
"I was heading north and one of the cars involved overtook me at Waiomio which was going rather fast in the rain," she said.
"[The] road was very slippery I only heard the crash noise and came around the corner to see the wreck. The car must have lost control or something".
She said the incident, which looked to have been a head-on collision, was bad and all the occupants appeared to be badly hurt.
A Fire and Emergency New Zealand spokesman said two cars had flipped on the road.
"Several people are trapped and we are working to extricate them," he said.
The NZ Transport Agency warned of delays soon after the crash.
"Motorists are advised to allow 100 minutes for the detour," it said.
A detour route for southbound traffic on SH1 at Ohaeawai: Turn right on to SH15, turn right on to SH1.
Northbound traffic is being told to turn left on to SH15 from SH1 at Otaika, and turning right on to SH1 again.
The incident comes after a horror weekend in which four motorcyclists lost their lives on New Zealand roads and this morning, a motorist died following a crash at Okere Falls, Rotorua.
Meanwhile, St John in Auckland has transported two people in serious conditions to Auckland Hospital following a crash in Mt Wellington.
A Fire and Emergency New Zealand spokesperson said a car crashed into a power pole earlier this afternoon.
The spokesperson said FENZ helped one person out of the vehicle after they were trapped following the incident on Hamlin Rd.
Elsewhere, six people have been taken to hospital in the Tasman district following a serious two-car crash in the Redwood Valley.
The incident occurred on State Highway 60, known as the Coastal Highway, around 4pm today.
A police spokesperson said some of the injured are believed to have sustained serious injuries and the road remains blocked.
More to come.
