The road at Maungaturoto on State Highway 12 has reopened after a fully loaded cattle truck and trailer crashed and rolled onto its side.
The crash at the corner of Whakapirau Rd and SH12 happened at 11.20am today.
Emergency services and locals helped free and contain some cattle while the truck was put back on the road.
The diversions through rural roads were short and did not significantly disrupt traffic flow.
The rail line at Maungaturoto also had to be closed during the incident.
The highway was opened again at 2pm.
ROAD CLOSED: 12.54pm
Motorists are being asked to take alternative routes around Maungaturoto as the road is closed following a serious crash.
The New Zealand Transport Agency has advised motorists to avoid the area or delay travelling on the SH 12 Dargaville to Brynderwyn as the road is closed due to what it described as a "serious incident".
Eastbound motorists are being asked to detour onto Ford Rd, to Huarau Rd, Whakapirau Rd and then back onto State Highway 12.
Westbound motorists can travel onto Gorge Rd, Griffin Rd and back to State Highway 12.
Emergency services are at the scene.