Motorists between Belgrove and Tapawera are being warned to take care as slips have fallen on the Spooners Range.
The State Highway is the main road used for those travelling between Nelson and Christchuch, the West Coast and now Marlborough, with the closure of the highway between Nelson and Blenheim.
An eyewitness says there were no signs up at around 3.45pm when he passed but motorists were slowing down and letting each other pass without problem.
The slips come after two days of rain that has lashed the region.
