NZTA said State Highway 25 was closed in both directions between Ruamahunga and Tapu.
“There are multiple trees down. NZ Transport Agency Waka Kotahi contractors are working with arborists to clear the site,” a statement said.
“Arborists will be clearing the trees this morning. We won’t know the scope of the slip until the vegetation is cleared.
“The road remains closed until further notice. Road users face a lengthy detour via State Highway 25A and State Highway 25 via Whitianga.”