A major weather system is set to bring heavy rain and strong winds to parts of Canterbury and the West Coast.
MetService said the front was expected to move northwards over Fiordland tomorrow and become slow moving in Westland during Wednesday and Thursday.
Orange heavy rain warnings are in force for Westland, south of Hokitika, from 9am Tuesday until 6pm on Thursday, and for Fiordland - about and north of George Sound - and the headwaters of Otago lakes and rivers from 9am tomorrow until Wednesday morning.
There was potential the warning for Westland south of Hokitika could be upgraded to red, Met Service said, as 600mm to 800mm was forecast to accumulate about the ranges, and 200 to 300mm about the coast.
The "significant heavy rain event" would bring peak rates of 20 to 30 mm/h about the ranges there, it said.
Meanwhile, heavy rain watches were in place from 9am tomorrow until 6pm on Thursday for the Grey District and the Westland District north of Hokitika, and for Fiordland south of George Sound for most of Tuesday.
The headwaters of Canterbury Lakes and rivers are also subject to a heavy rain watch from 9am tomorrow until Wednesday evening.
Strong wind watches are in place from 6pm today until 6pm tomorrow for Fiordland, and for the Canterbury High Country for 24 hours from noon on Tuesday.
Heavy rain was also expected to return to parts of Fiordland and the headwaters of Otago lakes and rivers later on Wednesday, with extended warnings possible.
The strongest winds on Wednesday would likely be about inland Otago, Canterbury and the Marlborough Sounds in the South Island, and in Wellington and southern Wairarapa in the North Island, the forecaster said.
