The MetService says there is a small chance tornadoes will hit the South Island this afternoon as severe thunderstorms lash the country.

Many parts of the country, including central and eastern regions are experiencing wild weather.

Fire crews were scrambled to call-outs in Carterton and at Tauherenikau in Wairarapa this morning after a shortlived burst of high winds twice caused power lines to arc, cutting power to more than 1500 homes.

Fire communications supervisor David Miekle said Greytown volunteer firefighters spent almost 20 minutes at the scene of arcing lines at Tauherenikau at about 8.44am.


Less than 10 minutes later a crew from Carterton was involved with arcing lines in the town for about the same period of time.

Powerco had field crews on standby and asked Wairarapa people to secure objects that could blow into overhead power lines as the severe winds picked up.

Power was cut to more than 1490 properties in the Carterton suburb of Carrington just before 9am and supply was restored to the vast majority by 9.30am.

In Greytown's Morisons Bush, power was cut to 230 customers at about 7.50am. Supply was expected to be restored by noon.

Powerco network operations manager Phil Marsh said: "Downed lines must be treated as live at all times and people should keep clear of them."

The storms are expected to bring northwest wind gusts of more than 110km/h and strike southern Westland, Fiordland and Stewart Island.

WeatherWatch head analyst Philip Duncan said the worst of the wind was reserved for inland north Canterbury, north of Christchurch, and Kaikoura later today.

At the same time there was a good chance Wellington would be walloped by hurricane force gusts tonight.

He said the country was entering a new weather pattern in coming weeks which would be marked by strong winds roaring across the country.

MetService this morning extended its wind warning to include central Hawkes Bay ahead of damaging gales, with 140km/h gusts, which are expected to lash the eastern coastline of both islands today.

MetService says there could be one or two small tornadoes in localised coastal areas.

Duckshooter Andy Tannock of Palmerston North struggling through waves as he abandons his maimai on Lake Wairarapa after storm force winds hit the region. Photo / Mark Mitchell
Duckshooter Andy Tannock of Palmerston North struggling through waves as he abandons his maimai on Lake Wairarapa after storm force winds hit the region. Photo / Mark Mitchell

"These squally winds and possible small tornadoes may cause some structural damage, including damage to trees and power lines, and make driving hazardous."

More heavy rain is expected to fall on already deluged western areas of the South Island and Southern Alps.

MetService has issued a warning for the whole of the West Coast with periods of rain expected through to Sunday, while the Westland ranges are forecast to get an additional 180mm of rain today.

MetService warns this amount of rain will cause streams and rivers to rise rapidly and could lead to slips, making conditions dangerous for trampers.

There is also a heavy rain warning for the Tararua Ranges north of Wellington.

The West Coast Civil Defence Emergency Management and Regional Council said it is monitoring all rivers in the West Coast at the moment.

The Waiho River that breached its banks in Franz Josef in March is not causing concern but a stretch of State Highway 67 north of Westport remains closed because of flooding this morning.

The road between Hector and Lamplough has become impassable because of flooding and debris and there are no detours in place.

The New Zealand Transport Agency is also cautioning drivers using the highway north of Westport to Mokihinui to beware of surface flooding.

The agency also issued a strong wind warning for motorists using the Rimutaka Hill today. They asked those on motorbikes or in high-sided vehicles to take care.

In Christchurch, authorities are urging high-sided vehicles and motorcyclists to take care as a high wind warning has been issued.