The Canterbury region is under the highest warning as severe gale-force winds move in on much of the South Island.

A red strong wind warning has been issued about and west of the foothills and west of State Highway 1, south of the Rakaia River, from 10pm today until 3pm on Sunday.

Meteorologist Michael Pawley said severe gale northwesterlies were expected to reach 150km/h in exposed places.

"There is a threat to life from flying items and falling trees. We're expecting destructive winds to cause widespread damage, including to power lines and roofs, with dangerous driving conditions and significant disruption to transport and power supply."

People are urged to avoid travel, stay indoors and prepare for power and communication outages.

In Canterbury, east of SH1 south of the Rakaia River, and away from the foothills further north, there is a lesser orange strong wind warning in place from 2am on Sunday, where driving may be difficult, especially for high-sided vehicles and motorcycles.

Pawley said most of the South Island had been upgraded to orange strong wind warnings with gusts of 120km/h expected in exposed places.

The warning applies to Westland District, Queenstown Lakes, Central Otago and inland parts of North Otago, Dunedin and Clutha, Fiordland and Southland. A strong wind watch is in place for the Grey District.

Meanwhile, an orange heavy rain warning applies on Sunday for the ranges of Westland, the headwaters of the Otago lakes and rivers, Fiordland about and north of Doubtful Sound, and for Buller and about the Spencer Mountains and St Arnaud Range.

The New Zealand Transport Agency/Waka Kotahi (NZTA) this afternoon urged road users to consider the warnings and advice from the MetService.

"If you are travelling, plan ahead and be prepared, drive to the conditions and take extra care in strong winds and heavy rain."

Plea not to light fires 

Fire and Emergency NZ is urging people to avoid lighting any outdoor fires this weekend due to extreme wind speeds forecast for Canterbury.

District Commander Rob Hands said in a statement today these winds would make any fires very hard to control and could easily ignite old fires that have not been completely extinguished.

Anyone who has had an outdoor fire in the last two weeks should check the site and make sure that it is completely out. Put water on the ash piles or embers if there is any sign of heat.

"We had a foretaste of this last Wednesday, when there were multiple fires across our region and our firefighters dealt with some very challenging situations due to preventable fires, he said.

"We want to avoid that happening again."

- additional reporting Allied Media