The South Island is in for a battering of gales and rain with the potential to topple trees and powerlines, and make driving dangerous.
MetService has issued a "top end" severe weather warning for much of the South Island as well as Wellington and Wairarapa.
Fiordland, the Westland Ranges and parts of Otago and Canterbury can expect heavy rainfall, with between 120 and 200mm of rain from tomorrow evening.
Meteorologist Georgina Griffiths said it was an unusual front and was strong even for the West Coast.
"This is quite a significant top end warning."
Gusts of up to 160km/h are expected to develop from tomorrow morning through Fiordland, Southland, Otago, Canterbury, Malborough and up to Wellington and southern Wairarapa.
Metservice says rivers and stream could rise rapidly, and there could be surface flooding.
It warns the strong winds could topple trees, powerlines and irrigation systems, and can make driving extremely hazardous, especially for motorcycles and high-sided vehicles.
Ms Griffiths said the bad weather would most likely affect the Fox Glacier area where rescue crews are currently taking advantage of a fine break to recover bodies from a helicopter crash.