The van was on its side and partially blocking one lane, she said.
St Johns, police and Fire and Emergency New Zealand were at the scene.
Meanwhile, emergency services are responding to a serious crash between a truck and a van on State Highway 6 near Richmond, south of Nelson.
The incident took place around 3.15pm on Richmond Deviation and there are reports one person is trapped inside the van. Crews were working to free them.
Traffic congestion is building and motorists are asked to avoid the area. Diversions are in place.
And two Christchurch children have been hit by cars within 10 minutes.
A police spokeswoman says a child was serious injured on Selwyn Street about 8.20am this morning.
And soon after in Hornby - a second child was hit by a vehicle at the intersection of Waterloo Road and Taurima Street.
The Otago Daily Times reports the child was taken to Christchurch Hospital with minor injuries.