Barratt said early indications pointed to possible issues with the trailer but said investigations were ongoing. The truck driver was unhurt.
It's the second logging truck crash in Northland this month.
On August 6 the door of a logging truck had to be prised opened with a crowbar to free the trapped driver after the truck and trailer unit rolled on a Northland road.
Police Sergeant Barbara Goodwin said it appeared the truck had been travelling south on SH15/Mangakahia Rd when the trailer went off the edge of the road, pulling the truck unit over about 12.05pm.
Logs spilled into a paddock and some went across the road, closing it to heavy traffic, north of Twin Bridges near Gammon Rd.
Light cars and vehicles were able to get around the crash site thanks to a farmer opening up a farm track for them to use.
Goodwin said volunteer firefighters from the Kaikohe Brigade helped get the male driver out of the truck. He had minor injuries. A heavy tow truck was used to right the truck unit.
The crash happened on a straight section of road which was dry at the time.
Goodwin said the cause of the crash was under investigation.