The New Zealand government is warning people in the middle of the country to avoid travelling, as damaging winds and rain are expected to hit the South Island and lower North Island later today.

Gusts of up to 150 km/h are forecast in exposed places from this afternoon in Canterbury, north of Ashburton, Marlborough, Wellington and the Wairarapa.

Gale warnings were in place across the South Island, storm warnings were issued for the lower North Island and wind warnings covered from Hawke’s Bay to the Canterbury Plains across to Westland.

The Westland district is expected to have the most rainfall – with as much as 300 to 400 millimetres falling in the ranges over 24 hours.

Government rain monitors showed a large band of heavy rain rapidly approaching Hokitika.

In a weather warning, the Govt weather agency said up to 40mm of rain an hour could fall in Westland at the peak of the storm.

The warning said the weather “bomb” could cause in flooding and slips. The winds could bring down trees and powerlines.

Meteorologist Lisa Murray said people in affected areas need to be aware.

She said rain in Westland will be heaviest this afternoon. Winds in Wellington are expected to start late today and go through until Thursday.

A low pressure system that deepens rapidly in a short time was known as a “bomb low”, the warning said.

“Rivers and streams will rise rapidly, including those in Canterbury that feed from the Alps.

“This event will especially impact anyone in the mountains, river users, tourists and those travelling on the roads.”

As the low moves off the country to the east on Thursday it will bring unseasonably cold overnight temperatures, which could bring snow overnight Wednesday through to Thursday.

The storm is likely to bypass Auckland and the upper North Island where summer highs are set to continue.

– Radio NZ