Wild weather is causing havoc in Christchurch leaving thousands without power, causing surface flooding on the roads, knocking down tree branches and lifting a roof of a house.

The storm has brought down branches from trees and cut power to thousands of homes in Christchurch and Banks Peninsula this afternoon.

A roof has lifted off a house in Sumner and loose roofing iron has also been swept off buildings in the central city.

More than four thousand homes in Christchurch and Banks Peninsula are without power.

Heavy rain has caused surface flooding on more than a dozen roads - including Papanui, Lincoln, Riccarton and Blenheim roads.

The fire service has received 30 calls since 4pm.

MetService meteorologist Andrew James said the bad weather hitting Christchurch at the moment will ease within the next hour.

"There's just a few showers in behind that front and then things will be noticeably better when it's gone."

However, Wellington should brace itself as a new system was expected to bring heavy rain and wind this evening before easing overnight.

Tomorrow the capital would be hit by bad weather again as the same front that caused havoc in Christchurch this afternoon moves north.

James said as the front moved north of Wellington the weather was unlikely to be as bad in the rest of the North Island due to a ridge forming over the country that would calm it down.

"Generally tomorrow will be a better day than today."

Western parts of the North Island including Whanganui, Palmerston North and Hamilton were also drenched with rain today, while Auckland and Northland had scattered showers.

The second part of the week looked better with fine weather expected in most of New Zealand.