Wind gusts have reached more than 140km/h in exposed parts of Canterbury and some flights in and out of Wellington have been affected as a cold snap brings heavy rain and gales to many parts of the country.

Wellington Airport spokesperson Phil Rennie says a number of flights had also been cancelled at Wellington Airport due to bad weather at other destination airports.

MetService has placed much of the upper South Island and lower North Island under heavy rain, strong wind or thunderstorm warnings.

Meteorologist Mmathapelo Makgabutlane told RNZ the strongest gusts so far have been recorded at Aoraki Mount Cook, while the heaviest rainfall had been seen in Marlborough.

"Twenty to even 40mm of rain in one hour - and that is mostly at the top of the South Island, especially in more mountainous areas. So quite a lot of rain to fall in such a short space of time."

Makgabutlane says conditions are now easing in the South Island, but they are set to intensify through the central North Island.

MetService earlier said a trough would bring unsettled weather to western parts of both islands, followed by heavy showers and thunderstorms across southern and central New Zealand.

Orange heavy rain warnings remain in place for the Tararua Range and for Mount Taranaki, and a severe thunderstorm watch is in force for Waikato, Waitomo, Taumarunui, Taupō, Hawke's Bay, Taranaki, Taihape, Wanganui, Manawatū, Tararua, Kapiti-Horowhenua, Wairarapa, Wellington and Marlborough until 6pm.

There is also a road snowfall warning for the Crown Range Road overnight.

Many other parts of the country are also subject to strong wind and weather watches until tonight.

For the most up to date changes, please check the MetService warnings page.

Meanwhile, gravel and silt which was washed onto Ballarat Street in Queenstown this morning, causing part of the street to be temporarily closed, had now been cleared.

A post on X by Waka Kotahi shows an image of water flooding across Ballarat Street in central Queenstown. Photo: Screenshot / X.

A post on X by Waka Kotahi earlier showed water flooding across the street in the centre of the town.

Queenstown Lakes District Council told RNZ the debris was from an existing road works site on the street and the small affected section of the street had now re-opened.

A review is due to be completed shortly to see what measures can be taken to prevent it from happening again, the council says.

The debris has not affected travel on State Highway 6A - Stanley Street - nor the road works where the debris originated from, it says.

-RNZ.