The truck's cargo - beer, large vats of honey, tyres and other goods - had shifted forward in the crash and was pushing up against the rear of the cab, so had to be removed before the driver could be freed.
Despite his injuries the driver was conscious and talking, but deteriorated rapidly around 9am as his legs were freed from the wreckage. He had suffered serious crush injuries to his lower body.
Police have yet to release his name but he is understood to be from Auckland. The other driver suffered only minor injuries and was taken to Bay of Islands Hospital by ambulance.
Fire Service Muriwhenua area manager Allan Kerrisk praised emergency personnel for a "tremendous effort in trying conditions."
"They are obviously disappointed with the outcome, but know they've done the best they could," he said.
Senior Sergeant Peter Robinson (Kerikeri) said emergency services had done everything they could to save the driver. He expressed his condolences to the family of the deceased, and asked motorists to be patient as the tragedy forced an extended closure of Kerikeri Road.
It was too early to say what had caused the crash or whether it could have been avoided. He did, however, appeal to motorists to drive with care, especially in rain and reduced visibility.
The Northland Electricity Rescue Helicopter also responded, landing first at Kerikeri Domain, then in a field next to the crash scene.
Local firefighters were backed up around 8.30am by a Whangarei crew. The road remained closed while a crane travelled from Whangarei to remove the wreckage and the police Serious Crash and Commercial Vehicle Investigation units examined the scene. Spilled diesel also had to be mopped up. The road was reopened following a blessing by Minister Sid Kingi.
The crash came one week into a month-long police campaign focusing on heavy traffic safety, targeting speed, fatigue and vehicle compliance.
Meanwhile the crash, and an earlier fatality on the East Coast, has prompted the First Union to call for "something" to be done.
"Something isn't right," spokesman Karl Andersen said.
"Is it because of fatigue, or the trucks are not maintained? Is it the standard of driving, or is it (that) we're pushing people into driving heavy vehicles when they shouldn't be?
Mr Andersen said a detailed analysis of every crash needed to be carried out to determine what, if anything, could be learned, adding that while truck crash deaths were falling, heavy vehicles were still statistically over-represented.