State Highway 59 between Paekākāriki and Pukerua Bay will remain closed until further notice, Waka Kotahi said.
"The highway has been closed since Friday after multiple slips.
"However, further assessments over the weekend show the slip site remains highly unstable.
"Making the site safe will be a significant job, and it could take several weeks before it can reopen to traffic.
"A further update on its status will be provided this Friday.