Western parts of Taranaki down to Westland in the South Island are in for a drenching, forecasters are warning.
The MetService has issued a severe weather warning for Mt Taranaki, Nelson, western Marlborough, Buller and Westland, saying the areas can expect heavy rain on Sunday and early Monday.
Up to 180mm could fall in the north-west ranges of Nelson on Sunday.
"A complex low pressure system, with a series of warm fronts, affects much of the country until early Monday, bringing rain to most places," the forecaster said.
It warned streams and rivers could rise rapidly, while surface flooding and slips were also possible and driving conditions may be hazardous.