Update: A slip which closed the southbound lane on State Highway 1 north of Mangaweka has been cleared and the road is now open.
The slip occurred just after 1am on Tuesday near the intersection with Manui Rd, just north of Mangaweka.
Waka Kotahi NZ Transport Agency advised caution.
The northbound passing lane on the road was used for southbound traffic.
Meanwhile, a severe weather watch has been issued for Tuesday, with Metservice warning strong deluges are possible in areas including Whanganui, Taihape and Taumarunui.
