A cold south-westerly wind that brought cold temperatures to the South Island is expected to spread across the rest of the country on Friday.

Meanwhile, temperatures in the Bay of Plenty will remain relatively high before dropping below the 10 degree mark on Monday night.

A cold south-westerly wind is expected to move up the country this week. Photo: File.

The MetService says the culprit for the chilly temperatures is colder air arriving over New Zealand from the Southern Ocean, which is set to bring cooler conditions to many this weekend.

'The combination of low temperatures and strong winds will also generate a significant wind chill factor,” says a statement from the weather organisation.

'Central New Zealand is also set to experience some blustery weather with a watch for severe gales also in place for Buller and Nelson along with Central Hawke's Bay and the Tararua District.”

That cold south-westerly wind is set to spread across the country on Friday.

Snow showers are also a possibility for a time later this evening on higher ground on the Desert Road (SH1).

Between 4pm and 8pm, one-to-two centimetres of snow could accumulate, with lesser amounts down to about 800 metres.

'The good news is there will be some fresh snowfall for many of the southern skifields and also for Mt Ruapehu,” adds the statement.

'Many Kiwis are already waxing their skis and boards in anticipation of the upcoming season, which is scheduled to commence for some fields this weekend.”

Accompanying the strong south-westerly winds will be large amounts of swell around southern and eastern coasts.

These swells should continue to push northwards beyond Aotearoa into the tropics, arriving in time for Ricardo Christie to ride at this year's Fiji Pro surf competition.