Wellington is under a severe thunderstorm warning, issued by MetService just as hail and a torrent of rain began falling on the city.

All flights through Wellington Airport have been stopped while two international flights were diverted to Christchurch and Auckland. The airport said travellers should check with their airlines for flight statuses.

Reporters based in the capital said the clear, sunny day quickly turned to darkness about 3pm as the storm rolled in.

One said her street had turned into “a river”, describing the sudden downpours as “insane”.

Hailstones measured up to 12mm, MetService said, with photographs supplied to the Herald showing streets and yards blanketed.

Hail and thunder rattled Wellington about 3pm on Tuesday, turning streets into rivers and blanketing them with hail. Photo / Katrina Bennett

A Fire and Emergency New Zealand staff member said they were getting “a few calls” about the sudden wild weather.

Thunderstorms, heavy rail, hail, strong winds hit North Island

Severe thunderstorms with heavy rain, hail and strong winds are heading up the east coast of the North Island.

MetService has issued a severe thunderstorm watch for Gisborne, Hawke’s Bay, Manawatū, Tararua, Kāpiti-Horowhenua, Wairarapa, Wellington, Marlborough, Christchurch and Canterbury Plains until 6pm tonight.

One Herald reporter said her street had turned into “a river”, describing the sudden downpours as “insane”. Photo / Katrina Bennett

The brutal storm hit Canterbury earlier this morning, flooding houses, delaying flights and cutting power to several properties.

Fire and Emergency New Zealand (Fenz) said heavy rain had flooded houses in the suburbs of Belfast and Middleton, RNZ reported.

Power company Orion confirmed four properties in Halswell/Tai Tapu lost power after a lightning strike, while properties in the Christchurch suburbs of Dallington and Harewood, and the town of Waddington, also lost power.

MetService is forecasting the storm will make its way up the east of the North Island this afternoon.

A spokesperson said: “Showers are forecast in Wellington after 2pm with the risk of thunderstorms.”

NZTA/Waka Kotahi is urging drivers in Wellington, Wairarapa, Tararua and Marlborough to keep an eye on the weather and road conditions.

“The forecast warns of hail, intense rainfall, damaging winds and the potential for hazardous driving conditions and poor visibility.

“Road users should watch their speed and following distances, avoid sudden braking on wet roads and turn their headlights on if visibility is poor.”

MetService is warning the thunderstorms are “expected to be accompanied by very heavy rain, large hail and damaging wind gusts”.

“Very heavy rain can cause surface and/or flash flooding in streams, gullies and urban areas, making driving conditions extremely hazardous,” a spokesperson said.

“Large hail can cause significant damage to crops, orchards, vines, glasshouses and vehicles, making driving conditions hazardous.

“Very strong wind gusts can break branches from trees, damage roofing and create hazardous driving conditions, especially for high-sided vehicles and motorcycles.”

The National Emergency Management Agency is advising residents on the East Coast to take shelter indoors, preferably away from windows, avoid sheltering under trees if outside, get back to land if outdoors on the water, move cars under cover or away from trees, secure any loose objects around property, check that drains and gutters are clear and be ready to slow down or stop if driving.

A lightning strike may have been behind a hedge fire at Yaldhurst outside Christchurch this morning. Photo / George Heard

Canterbury residents took to social media to share images of the hailstorm that hit the region just after 9am.

One resident said: “[It] was mental in Methven. [I] could hear the hail coming before it got to my house.”

Another said: “Just had hail the size of large marbles at Glentunnel! The storm lasted so long!”

Large hailstones have fallen in North Canterbury this morning. Photo / Laura Mitchell

Fenz crews responded to a hedge fire in the Christchurch suburb of Yaldhurst at 10.18am.

A spokesperson told the Herald: “There was a possibility it was due to a lightning strike but we are unable to confirm at this stage.”

Hail fell across Canterbury this morning.

Christchurch Airport confirmed this morning that it had “lightning strikes across the campus, which has impacted airfield lighting and navigation systems”.

“Some flights have diverted to other centres and some are delayed.”

By midday, the lighting had rolled north of the airport and it was operating as usual.