Weather: Jacinda Ardern's Invercargill flight cancelled as bad weather hits South Island

Prime Minister Jacinda Ardern has been forced to drive to Dunedin to hopefully catch a flight after her scheduled departure out of Invercargill was cancelled.

The Labour leader was in Invercargill on the campaign trail on Monday morning and was due to leave later in the day, but bad weather meant her original flight was cancelled, a spokesperson for Ardern confirmed.

The Antarctic blast sweeping New Zealand caused heavy rain, gale-force winds and cold temperatures over the weekend, and snow had fallen in many parts of the South Island.

Ardern posted a photo to Facebook on Monday morning with Labour volunteers in "snowy Invercargill" who were out waving the party's signs in "2C weather".

Many flights to and from Queenstown and Invercargill airports were cancelled on Monday as the severe weather hit. Dunedin Airport currently has no flight cancellations for Monday afternoon, according to its website.

NZTA also said the adverse weather meant some state highways had to close while snow was removed from the road.

MetService forecasts that Tuesday will be the coldest day for the South Island, but it will start to warm in the far south by early Wednesday.