MetService is warning of potential thunderstorms across the North Island and top of the South Island and snowfalls in parts of the country.
It said much of the country should prepare for a dramatic temperature drop by Wednesday
A severe weather watch has been issued for Taranaki, Wanganui, Manawatu, Kapiti-Horowhenua and Marlborough on Monday night and Northland, Auckland, Great Barrier Island and the Coromandel Peninsula on Tuesday.
MetService says showers and thunderstorms are forecast and there may be damaging gusts of up to 120km/h in exposed places.
Meanwhile, snow has been falling in parts of South Otago on Monday.
Snow is also predicted overnight for the Desert Road in the central North Island, on Milford Road in Fiordland and on the South Island alpine passes.
New Zealand Transport Agency spokesperson Andy Knackstedt said warnings are in place in Otago and Southland and people should drive to the conditions.
Mr Knackstedt said State Highway 94 at Milford Sound remains closed for rock face stabilisation.
