State Highway 6 in South Westland is closed, as heavy rain continues to pile onto the West Coast.
Overflow from the waterfalls in the Haast Valley is running down the highway at the Mahi Tahi River south of Bruce Bay.
Up to 700 millimetres of rain could make landfall by midday on Thursday.
Waka Kotahi West Coast maintenance contract manager Moira Whinham.
