Aucklanders and those in Bay of Plenty will be treated to high temperatures and clear skies as they celebrate the Auckland Anniversary long weekend, while other parts of the country will also swelter.

A large high pressure system sitting over the country is likely to bring high temperatures, MetService says, with some centres forecast to break the 30-degree mark.

"Parts of the South Island are also set to warm up to more summer-like conditions, with areas east of the ranges rising to the high 20's and even the low to mid 30's on Saturday," MetService said.

"This time the hot spots are the result of building northwesterly winds across the South Island, linked to approaching fronts."

Tauranga is expecting a scorcher, with daily highs of up to 30 degrees from Friday to Monday.

Auckland city will reach at least 27 degrees on each day of the long weekend, while Hamilton can expect temperatures of up to 31 degrees.

In the capital, Wellingtonians can expect a fairly-warm 25 degrees on Saturday and Sunday, with a little cloud on Sunday.

Cantabrians can also expect high temperatures, especially on Saturday, with a high of 32 degrees forecast for Christchurch.

Source: TVNZ.co.nz