Heavy rain and snow are expected for parts of the South Island, while central New Zealand may experience southeasterly gales over the rest of the long weekend.
MetService said a front, preceded by a moist northwesterly flow, was expected to move over the south of the South Island early Sunday, with a low then forming a front to the west of Westland.
The front and low move northeast over central and northern New Zealand from Sunday afternoon to early Monday, bringing rain to most places, with brief heavy falls likely in the west of the South Island.
Coromandel, Gisborne, Hawkes Bay and Westland are under heavy rain watches.
Much colder southerly winds follow the front, which should bring the snow level down to around 500 metres in Marlborough, Canterbury, Otago, Southland and Fiordland.
Road snowfall warnings have been issued for several of the South Island mountain passes for Sunday, with MetService warning of potential travel disruptions.
Strong wind watches have also been issued for Taranaki, Wellington and Marlborough Sounds, where south to southeast winds may approach severe gale at times.