File pic Photo: 123RF
Severe weather warnings are being issued for parts of the South Island with more than a month's worth of rain set to lash the West Coast in the coming days.
MetService has warned more than 500mm of rain is expected to accumulate about the West Coast ranges from tonight through to Thursday morning.
The deluge could cause surface flooding and slips with rivers and streams to rise rapidly.
Orange level rain warnings are in place for Fiordland, Westland and Buller from tonight with strong wind warnings extending to Fiordland and the Canterbury High Country.
Rain warnings will be in place for the headwaters of lakes and rivers in Otago and Canterbury.
Westland was expected to get the most prolonged spell of rain with a warning in place from overnight tonight through to 9am Thursday.
Between 400 to 550mm is forecast to accumulate on the ranges between Ross and Bruce Bay, but MetService has suggested rainfall could exceed these levels.
Up to 150mm was forecast about the coast.
MetService metrologist Lewis Ferris said there had been discussion with regional leaders around warnings being escalated to red-level.
He said the deluge would be a lot, even by West Coast standards.
"We're talking about more than a month's worth of rain falling in that time period," he said.
"We all know, the West Coast tends to get a lot of rain, but this is even going to be on the upper side of the limits for them.
"So it's still sticking at an orange warning, but forecasters have been talking with the regional council and debating whether or not that could get elevated to a red and that is still a chance."
Rain warnings are also in place for Buller between 6am and 10pm tomorrow, but this could be extended.
Up to 180mm of rain was expected about the Buller ranges with between 40 to 80mm elsewhere in the region.
Civil Defence officials on the coast have already begun preparations alongside other agencies.
A wider group meeting was due to be held on Tuesday afternoon.
West Coast Civil Defence group manager Claire Brown said residents needed to keep up to date with the ongoing warnings which would be issued over the coming days.
"With the rainfall amounts forecast we could see some impact across the southern parts of the region in particular," she said.
"It's important that people know what may happen as the event unfolds and take the necessary precautions."
Sandbags were being made available at a handful of spots in Hokitika from this afternoon.
Waka Kotahi NZ Transport Agency said motorists should take heed of the forecast along the West Coast.
Journey Manager Tresca Forrester said with heavy rain falling in South Westland and south of Arthur's Pass from the early hours of Wednesday, slips and surface flooding could be a factor.
"Please check the MetService warnings if you are driving along State Highway 6 or in Fiordland," she said.