There've been downpours on Northland, Auckland and Coromandel, as a month's worth of rain in just two days has begun

Part of the roof has been ripped off the Gables Restaurant in Russell.

The Gables, New Zealand's oldest operating restaurant, was built from pit-sawn kauri in 1847.

Also in the Bay of Islands, Paihia volunteer firefighters have helped rescue a large catamaran that beached at Paihia in strong winds and torrential rain.

Civil Defence Northland says both Top Energy NZ and Northpower are dealing with a few unplanned outages, but they're being resolved quickly.

State Highway 1 at Dome Valley was closed both ways earlier because of a slip.

It was later cleared enough for northbound traffic to pass through, however all southbound traffic is being detoured vis SH16, adding an extra 40 minutes to the journey.

Auckland has been told to prepare for 26 hours of intense rain between now and tomorrow morning.

Coromandel Peninsula has been warned to prepare for between 150 and 200 millimetres of rain from early morning to late tomorrow.

Purerua has seen wind gusts around 87km/h and Kaikohe has had winds up to 72km/h and 53mm of rainfall since midnight, often with 10mm falling per hour.