Early morning commuters are seen as a light rain falls over parts of Sydney [Source: Reuters]

More than two months’ worth of rain in one day has brought flooding and a state of emergency to the New Zealand city of Dunedin.

Forecasters MetService issued the a rare red weather warning on Thursday, its first anywhere in New Zealand for in 18 months, warning of threats to life and property.

While no loss of life or injuries have been reported, the deluge arrived and then some: the South Island city was lashed with its wettest day in more than a century.

Roads have been washed away in landslips, paddocks have been turned into lakes and about 100 people were evacuated from low-lying properties.

Climate agency NIWA observed 131mm of rain in the 24 hours to 9am on Friday, with MetService forecasting at least another 40mm on Friday.

Flooding has closed around two dozen roads including the arterial state highway 87, while a landslide closed state highway 88 to Port Chalmers, a popular tourist route.

In a blow to farmers, the big wet arrived during lambing and calving season.

A golf club and the Forysth Barr Stadium, the home of the Highlanders Super Rugby side, have been used to house evacuated and worried residents.

While there are concerns over sewage leaking into floodwaters, authorities have been delighted with their preparations and the response of locals.

Emergency Management Minister Mark Mitchell said the response had been “gold standard”, and Dunedin Mayor Jules Radich agreed “things are going as well as they can”.

“We can’t control water from the sky,” Mr Radich said.

“The situation is quite significant out there and there’s still a hell of a lot of water on the surface.”

Otago Civil Defence group controller Matt Alley urged locals to conserve water, and to “please stay home and stay off those roads”.

“There’s a level of unpredictability about how rivers and streams will behave and they could overflow,” he said.