A cold front is expected to move northwards over New Zealand on today and tomorrow.

The MetService says this is preceded by a strong northwesterly flow, and followed by colder southwesterlies.

"Severe Weather Warnings and Watches have been issued for this event, and this extends into Friday morning for gale or severe gale northwesterlies about the lower North Island," says the weather organisation in its latest severe weather outlook update.

"Consequently, there is a moderate risk of severe gale northwesterlies about Marlborough, Wellington, Wairarapa, Tararua District and Central Hawke's Bay on Friday morning. For more details regarding the current Watches and Warnings, see https://www.metservice.com/warnings/home."

Over the weekend, northwesterlies will strengthen again over the country as another series of fronts move onto central and southern New Zealand.

The MetService says there is moderate confidence of warnable rainfall amounts over Fiordland, Westland and the Canterbury/Otago headwaters later Saturday and Sunday, and low confidence over Buller, Kahurangi National Park and the Tararua Range on Sunday.

"Additionally, there is moderate confidence of another period of severe northwest gales about northern Marlborough, Wellington, Wairarapa, Tararua District and Central Hawke's Bay on Sunday and Monday morning.

"There is low confidence of severe northwest gales about other exposed parts of southern Marlborough, Canterbury, Otago, Southland and southern Fiordland later Saturday and into Sunday or early Monday, and also low confidence of severe gale west or southwest winds about southern Fiordland, Southland and Otago (mainly near the coast) later Sunday and early Monday.

"Finally, there is low confidence that westerly winds could reach severe gale about other North Island areas from southern Northland to Hastings District and Kapiti, and also near Golden Bay, later Sunday and Monday."