Weather warning for Wellington, Westland

The heaviest falls were expected to pelt the west of the South Island between now and early tomorrow.

The lower North Island and the South Island's West Coast and Buller regions have been told to brace for a wet and windy start to 2017.

The MetService has tonight issued a severe weather warning for Westland, Buller and the Tararua ranges, forecasting heavy rains.

"An active front is forecast to move east over southern and central New Zealand tonight and Sunday and weaken over the central North Island on Monday," the MetService said.

The front would bring "strong moist northerlies and rain" and the MetService advised people in the affected areas, particularly trampers, that rivers and streams could quickly rise.

The heaviest falls were expected to pelt the west of the South Island between now and early tomorrow.

Up to 200mm of heavy rain would fall in the Tararua Ranges between tomorrow morning to early Monday morning.

Wellington and the Wairarapa will battered by severe northwesterly gales, with the MetService issuing a strong wind warning for these areas.

Gusts of up to 120 kmh could sweep through exposed areas tomorrow and early Monday.

Winds of that strength could "damage insecure structures and make driving hazardous for motorcycles and high-sided vehicles" - particularly those using Rimutaka Hill Rd, Metservice said.

Inland parts of Canterbury and Marlborough could also be hit by northwesterly gales between now and late on Sunday.

As well as the warnings, Metservice issued a heavy rain watch for northern Fiordland and low lying parts of Horowhenua from now until tomorrow morning.

Another heavy rain watch was in place for Mt Taranaki and areas of Canterbury near lakes and rivers from tomorrow until Monday morning.

Falls of more than 80mm in 15 hours would spark a warning to be issued.