Heavy rain set for parts of North Island, weather watches in place

Heavy rain is on the way for parts of the North Island, with residents told to expect up to 40mm per hour in some areas.

MetService said water could run off and pool on the hard, dry ground, meaning a chance of flooding in some places.

The forecaster has issued a heavy rain watch for Northland (south of Dargaville) and Auckland (excluding Great Barrier Island).

It would be in force from 12pm Sunday until 10am Monday, and possible downpours and intensities of 20-35 mm per hour could be expected, MetService said.

The amount of rain could approach warning criteria in some places, especially in the west.

The culprit was a "very moist air mass" affecting the north of the North Island, the forecaster said.

Bay of Plenty was next in the firing line, with a "shallow low" expected to form to the west and downpours expected. A heavy rain watch would be in place there from 9am Monday to 12am Tuesday.

Rain would be heaviest inland and, like in Auckland and Northland, the amount could approach warning criteria, MetService said.

Up to 40mm of rain per hour could be expected.

"Further heavy rain is possible on Tuesday and the period of this watch may be extended," MetService said in a statement.

Locals were urged to keep up to date with the latest forecasts in case the situation changed.

On Saturday, orange weather warnings were in place on the West Coast as rain pummelled the South Island, but those had since been lifted.

The rain comes after at least a month's worth of dry days for much of the country over summer.

It was particularly dry in the North Island - Whanganui had the most dry days of anywhere in New Zealand, with 64.1.

Auckland had 53.8 dry days and Bay of Plenty had 59.6.

"While this is welcome rain after such a dry February, these peak intensities coupled with hard, dry ground can cause water to run off and pool, meaning there is a chance of surface flooding in localised areas," MetService said.