A heavy rain warning is in place for part of Fiordland, with up to 170mm forecast.
MetService said a slow front would move onto Fiordland, bringing the rain from noon today.
It would move over the area on Friday morning and afternoon, before heading for Westland and into Otago.
The Orange warning for Fiordland, south of Milford Sound, was in place from noon today until noon on Friday.
Between 150mm to 170mm of rain was forecast and thunderstorms were possible.
MetService warned that streams and rivers could rise rapidly. Surface flooding, slips and difficult driving conditions were possible.
"Clear your drains and gutters to prepare for heavy rain. Avoid low-lying areas and drive cautiously," it said.
Meanwhile, a heavy rain watch is in place for Fiordland, about and north of Milford Sound, from 7pm today until 6pm tomorrow.
Periods of heavy rain were expected and the watch could be upgraded to a warning, MetService said.
But by the weekend there would be plenty of dry weather to enjoy.
- Allied Media
