Locals used farm machinery to lift a tractor off the driver's arm when he was thrown off and trapped underneath in a crash on Mangakahia Rd.
The accident occurred at Awarua, about 20km south of Kaikohe, around noon on Monday.
Senior Sergeant Brian Swann, of Mid North police, said it appeared the tractor driver had failed to indicate or check for traffic before turning right into a farm driveway and was side-swiped by an overtaking Top Energy ute.
He was thrown off and pinned under the tractor by one arm.
The tractor driver was initially described as being in a critical condition so the Northland Rescue Helicopter was dispatched from Whangarei.