The West Coast Regional Council is closely watching the coming weather and deploying staff in Westland over the weekend.
MetService has issued an orange rain warning for Westland from 9pm Friday till 8am Saturday, with up to 200mm of rain forecast about the ranges, and 70 to 120mm near the coast.
Significant short-duration heavy rain of up to 250mm is expected around the glaciers.
Council chair Peter Haddock said the predicted rainfall would be short-lived over Friday night into Saturday morning.
He said council was keeping a close eye on the Waiho River, which was now almost entirely flowing into the neighbouring Tatare Stream after last weekend's deluge.
But the township, roading network and people were at no immediate risk, he said.
MetService said people in the Westland District should stay vigilant and watch for weather warnings.
Severe gales are also expected overnight in the Canterbury High Country which MetService warns could damage trees and powerlines.
The weather front will move north over southern and central New Zealand through Saturday.
There are heavy rain watches for Tararua, Kapiti-Horowhenua, Wairarapa, Wellington, Taranaki.
MetService has also issued strong wind watches for Wairarapa, Wellington, Southern Lakes, Southland, Westland and Fiordland.