The trailer on a heavy motor vehicle rolled onto its side and blocked the road near Gore this morning.
A police spokeswoman said police attended the scene between Pukerau and Gore at 5.10am.
She said a heavy motor vehicle was travelling south on State Highway 1 when the trailer unit left the road and rolled onto its side in the water table near Mason Rd.
A New Zealand Transport Agency spokeswoman said both lanes near the intersection of Coalpit Rd were blocked about 7.30am.
It was expected clearing the road would take 45 minutes but it only took 20, she said.
There were no injuries reported in the incident.
The police spokeswoman said inquiries were continuing.
