Westland is likely to be escalated to a red heavy rain warning Wednesday following a night of intense rain, MetService says.

Red weather warnings are only used for the most severe storms, such as Cyclone Gabrielle in 2023.

The forecaster said it only issued red warnings when it expected widespread significant impacts, disruptions or safety issues.

Westland District south of Hokitika is forecast to receive heavy rain through to 9pm on Thursday.

Orange heavy rain warnings are also in place for Fiordland north of George Sound, headwaters of Canterbury lakes and rivers south of Arthur's Pass and headwaters of Otago lakes and rivers.

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There has been a significant amount of rain in south Westland overnight, West Coast Emergency Management group controller Te Aroha Cook says.

In Franz Josef, close to 300mm of rain had fallen since yesterday, she says.

The Franz Josef community has been proactive in shifting stock or people in low-lying areas evacuating, so civil defence did not need to respond at night.

Today its focus will be continuing to monitor impacts on rivers throughout Westland.

SH6 from Fox Glacier to Haast remains closed due to a slip.