MetService says a ridge of high pressure should bring a minimal risk of severe weather to New Zealand during Tuesday and Wednesday.

"On Thursday, a large trough of low pressure is expected to move from over the Tasman Sea onto New Zealand, then move across the country on Friday followed by a strong and unsettled westerly flow," says a MetService spokesperson.

"Rain with heavy falls and strong west or northwest winds are expected in parts of the country from Thursday afternoon and during Friday."

For Westland and northern Fiordland, MetService says there is moderate confidence that rain will exceed warning thresholds during Thursday and Friday; while for Buller, the west of the Tasman District, and the headwaters of the Canterbury lakes and rivers, confidence is low that rainfall amounts will reach warning thresholds during Thursday and Friday.

For the Richmond and Bryant ranges of Nelson and Marlborough, Taranaki, Auckland, Coromandel Peninsula, and Northland, there is low confidence rainfall amounts will reach warning thresholds during Thursday. While for central and southern Fiordland, and also the eastern Bay of Plenty ranges, there is low confidence for significant rain accumulations during Friday.

"Additionally, there is low confidence for northwest or westerly winds rising to severe gale in exposed places during Thursday and Friday from Taranaki across to central Hawke's Bay, and down to central Canterbury, especially in the lee of any hills and ranges."

MetService also say that westerly winds could rise to severe gale on Friday about southern areas of Fiordland, Southland including Stewart Island, and Clutha.