The Transport Agency says the northern tip of the North Island will remain cut off all weekend following a washout on State Highway 1 about 40km north of Kaitaia.
The washout happened mid-Friday afternoon, taking out both lanes south of Pukenui between Whalers and Lamb Roads. Pictures show a gaping hole in the road.
The NZTA says the washout is significant, and with no alternative route it's advising motorists in or heading to the Far North to delay their journeys.
It's working with Civil Defence, emergency services and local authorities on a response to support people living in the area affected.
Around 1000 people were expected to attend a fishing event on Ninety Mile Beach.