Two calves had to be put down and a woman was flown to hospital with suspected broken legs after a crash south of Kaikohe.
Kaikohe fire chief Bill Hutchinson said the accident occurred about 2.10pm on Monday when a van towing a trailer loaded with calves left Mangakahia Rd near the aerodrome.
The van, which had been travelling north, crashed through a fence, across a paddock and into a large drain. The impact pushed in the front of the van, trapping the driver by her legs.
Two crews from Kaikohe Fire Brigade used hydraulic cutting equipment to free her.
For the first time in Northland two paid firefighters from Whangarei accompanied paramedics on board the Northland Rescue Helicopter in case they were needed to help extricate the driver.