A police van with two staff and five prisoners on board left State Highway 2 in icy conditions in the Wharerata hills near Gisborne this morning.

Police, Fire and Emergency NZ and St John Ambulance were called out at 6.40am.

"The van slid off the road and into the bushes alongside the highway," a police spokesman said.

"It remained on its wheels."

The van was travelling south to Hawke's Bay when the mishap occurred.

The staff, four male prisoners and a female prisoner were checked out at the scene by ambulance staff.

"None of them were injured," the spokesman said.

The prisoners were transported back to Gisborne in another van.

Police have issued a warning to motorists about the icy conditions in the Whareratas.

"The responding emergency vehicles this morning also encountered very icy conditions on the Wharerata road," police said.

In another icy road-affected incident, a freight truck went off the road near Otoki Orchard on State Highway 2 at Whakaki.

That incident happened at about 6.35am.

The truck ended up in a roadside drain but stayed on its wheels.

The driver was not injured.

- Gisborne Herald