Source: Stuff.co.nz

Surface flooding and potentially damaging winds will hit parts of New Zealand on Monday, with widespread heavy rain and gales predicted.

MetService issued a severe weather warning for rain and wind in many parts of the upper South Island and central North Island on Monday.

The rain moved on from the west of the South Island on Sunday night and is on its way to Nelson, Wellington, Taranaki, Tongariro National Park and the eastern ranges of Bay of Plenty on Monday morning.

Largest accumulations are likely in the ranges of Nelson and Mt Taranaki, where more than 200 millimetres of rain may accumulate in a 24-hour period.

More
http://www.stuff.co.nz/national/68066277/heavy-rain-and-gales-ahead-for-much-of-the-country

Source: weatherwatch.co.nz

It's going to get pretty hairy in places today - as several systems are going to influence conditions around the country in the form of both rain and wind.

A front is moving across the country, preceded by a strong northeasterly airflow, meaning gales for many places - pretty much anywhere exposed across the North Island.
Those winds then change northwest as the front moves through in the afternoon - so from early to mid afternoon it will affect the west, and later on the east.

More:
http://www.weatherwatch.co.nz/content/rough-stuff-weatherrisks-monday