MetService says a cold front will be spreading gale southwesterlies across much of New Zealand during Saturday and Sunday.

"The strongest winds are likely to be about eastern parts of Otago and a Watch for severe gales is in force," says a MetService spokesperson.

The Strong Wind Watch for Otago is in place for 19 hours from 3pm Saturday, May 25, to 10am, Sunday, May 26, with southwesterly winds forecast to approach severe gale in exposed places.

On Monday the strong southwesterly flow over the country is expected to continue to ease, with minimal risk of severe weather.

On Tuesday, a southwesterly flow will be covering most of New Zealand, with an embedded weak front forecast to move onto the far south at night.

Meanwhile, a shallow low over the Tasman Sea may spread rain onto the north of the North Island on Monday night. There is minimal risk of severe weather affecting New Zealand.

Cold southwesterlies strengthen over southern New Zealand on Wednesday, May 29, while a shallow low may move eastwards across the north of the North Island. There is low confidence of severe southwest gales about eastern parts of Dunedin and Clutha.

On Thursday, May 30, a strong west to southwest flow is forecast to cover the country, with an embedded weak front forecast to briefly affect southern New Zealand. There is moderate confidence of severe west to southwest gales about Stewart Island and coastal parts of Dunedin, Clutha and Southland.