A heavy rain warning has been being issued for Fiordland, with the region set to be soaked.
A front was expected to move across from Thursday afternoon and into the evening, bringing heavy northwest rain, MetService said on Wednesday.
The amount of rain may approach warning criteria between 12pm and midnight, the forecaster said.
Locals and holidaymakers were advised to keep up to date with the latest forecasts.
MetService also said there was "low confidence that Westland will receive warning amounts of rain, mainly about the ranges" on Friday as a front moves up the South Island.
Better weather was expected over the weekend for the whole country.