Westland District Council has activated its Emergency Operations Centre as river levels approach those last seen during the devastating 2016 floods.
Fox River Bridge taken from the south side earlier today. Photo: Supplied / Transport Agency
The council said the intensity of falls is expected to increase during the day and not let up until early tomorrow morning.
It said residents are asked to stockpile drinking water as water supplies could be affected.
Motorists are being warned about slips and surface flooding after heavy rain in Fiordland and Westland.
The Transport Agency said drivers should take care on State Highway 94 from Te Anau to Milford Sound.
It said heavy rain has caused two slips, closing SH6 between Franz Josef and Fox Glacier about 6.50am.
Surface flooding was also affecting many areas along State Highway 6 between Ross and Haast.
Westland District Council mayor Bruce Smith told Morning Report an "incredible" amount of rain had been forecast, with predictions of between 600mm and 800mm to fall.
"To get this sort of figure, I don't recall it in the last six or seven years."
He said rivers in the region were getting close to the heights of the April 2016 flood which caused "$30 million worth of damage".
"And they're rising quite rapidly in the last hour ... we've had a huge amount of rain overnight and we're expecting it to continue."
People needed to stay off the roads as there was considerable surface flooding, he said.
And he said people should contact the authorities if they noticed creeks overtopping banks so they can alert the public about it.
"It's incredible" - Bruce Smith
MetService said that by 7am, 430mm of rain had fallen in Milford Sound and 220mm at Mt Cook.
Meterologist Stephen Glassey said more was expected on the West Coast today.
"In Fiordland the rain will actually ease to showers this afternoon but in Westland we're expecting the heavy rain to get even heavier.
"We've still got the warning in place for Westland south of Ōtira where we're expecting possibly over 500mm of rain to accumulate about the ranges."
Mr Glassey said up to 30mm of rain was falling every hour overnight in Milford Sound.
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