Gusts could reach 130km/h in the Canterbury high country, and up to 120km/h in Fiordland, Southland, Stewart Island, Central Otago, Clutha and inland Dunedin.
Forecasters said strong gusts could damage trees, powerlines and unsecured structures and make driving conditions dangerous, especially for motorists in high-side vehicles and motorbikes.
Heavy rain is forecast for parts of the South Island's West Coast, including Buller and Westland, the headwaters of the Canterbury lakes and Fiordland, where weather warnings had been issued.
Looking ahead, a second weaker front is expected to move across much of the country on Saturday, followed by a narrow ridge, then a trough for the South Island on Sunday.
A series of active fronts, sitting within a strong northwest flow, will move onto the South Island on Monday.
The fronts are expected to bring periods of heavy rain to the western districts.