The Buller District has declared a state of emergency ahead of heavy rain expected to last until Friday, which could cause flooding.
Mayor Jamie Cleine declared the state of emergency at 2:35pm on Wednesday. The declaration "provides for controllers to direct and coordinate personnel, material and other resources made available", and can be used to grant "extraordinary powers to deliver an effective and timely response", the council's website said.
The Buller district is expected to be hit with 350-450mm of rain in the ranges and 180-230mm on the coast from 1pm on Wednesday to 11pm on Friday, according to MetService.
"This rain is expected to cause dangerous river conditions and significant flooding," the forecaster said. "Slips and floodwaters are likely to disrupt travel, making some roads impassable and possibly isolating communities."
People in the Buller District are advised to prepare getaway bags in preparation for potential evacuation.