Heavy rain is predicted this weekend over extensive areas of the country with Metservice issuing a rare red weather warning for most of Canterbury.
The meteorological service claims red warnings are reserved for only the most severe weather events.
Extensive areas of the Canterbury region can expect downpours that could cause treacherous river conditions and expansive flooding.
On May 28, Metservice warned, "slips and floodwaters are likely to disrupt travel, making some roads impassable and possibly isolating communities."
Other areas predicted to be impacted by the wild weather include the top of the south with heavy rain expected in Nelson west of Motueka, and possibly the Richmond Ranges.
Eastern Bay of Plenty, Taranaki, Northern Canterbury and Marlborough could expect similar conditions.
The wet weather in the South Island will be a result of a complex low-pressure system that is forecast to move slowly out of the Tasman Sea and shift across central and northern areas.
As much as 300mm of rain could fall in the Canterbury High Country and foothills during this time. Up to 120mm is possible for the plains and coastal area.
Heavy snow is expected at the same time and could fall as low as 1000 meters in some places in the region.
For the garden city, showers are predicted to change to rain and could be heavy at times on May 29. Southerlies will slowly change to easterlies and become strong. A chilly high of 12 is expected.
The city is expected to have rain with heavy falls and strong or gale southeasterlies on May 30. The wild weather is forecast to ease on May 31.
The Christchurch City Council told Stuff it had a course of action in place to try and reduce the risk of flooding.
The council said contractors were checking and clearing stormwater gates before the weekend.
“The combination of king tides and heavy rain is likely to result in some surface flooding, particularly in tidal areas and near the rivers,’’ acting head of Three Waters and Waste Tim Drennan said in a council statement.
He added pumps would be on standby in New Brighton and Flockton.
In other areas of the country where there is a possibility of heavy rain, the falls are expected to be scattered during the day on May 29.
While Aucklanders are not forecast to have such cold weather, the city will not escape showers, the possibility of squally thunderstorms and hail on May 29. The expected high is 16C.
For May 30, a few showers, possibly heavy, are forecast mainly after lunch and windy weather is expected throughout the weekend.
The capital is expected to have some wet weather on the afternoon of May 29 and a high temperature of 14.
On May 30 Wellington is expected to have dry conditions with light winds.
