MetService has issued its first batch of severe weather watches for an incoming blast next week.
An intense trough of low pressure is forecast to bring heavy rain and widespread northwesterly gales to western and northern parts of both islands.
This will be followed by a cold southwesterly flow with heavy showers and thunderstorms across southern and central New Zealand.
"This unseasonably cold outbreak may bring snow down to 1000 metres over Fiordland [and] the ranges of Otago on Monday," MetService warned.
"Large southwest swells are also expected for western and southern coasts later on Monday."
The forecaster added further watches and warnings for northern regions are likely.
Heavy Rain Watches
Area: The ranges of the Westland District
Period: 10hrs from 2am - noon Mon, 4 Mar
Area: The Otago Headwaters
Period: 8hrs from midnight Sun, 3 Mar - 8am Mon, 4 Mar
Amounts may approach warning criteria within 15 km east of the Divide.
Area: Fiordland north of Doubtful Sound
Period: 9hrs from 10pm Sun, 3 Mar - 7am Mon, 4 Mar
Heavy showers and thunderstorms, with alpine snow, likely through Monday morning and afternoon.
Strong Wind Watches
Area: Canterbury High Country
Period: 10hrs from 11pm Sun, 3 Mar - 9am Mon, 4 Mar
Winds easing from the south Monday morning.
Area: Central Otago, including the Queenstown Lakes District
Period: 7hrs from 10pm Sun, 3 Mar - 5am Mon, 4 Mar
Area: Fiordland, and Southland from Mataura northwards
Period: 6hrs from 9pm Sun, 3 Mar - 3am Mon, 4 Mar
