State Highway 1 was closed at Double Crossing, 7km south of Kaitaia, for around two hours after a tractor overturned, coming to rest on its side.
The driver, initially reported as being trapped, emerged unscathed in the accident on Saturday afternoon.
He confirmed what a witness had said, that he had lost control when the bucket fell off and the tractor drove over it. The witness added that the machine appeared to have struck a bump on the road as it travelled on to the bridge.
The Kaitaia Fire Brigade sent two crews, who diverted traffic via Clough and Ruaroa roads, the highway finally being cleared at around 4pm.
Fire brigade Station Officer Kaye Ah Sam said a tow truck from Kaitaia had got the tractor as far as a metal pit outside the Pamapuria substation, several hundred metres from the bridge, the owner taking over from there.