Rain is expected this week across New Zealand, bringing some relief, following the high temperatures of last week.

The humidity, however, is set to continue in central and northern areas.

On Tuesday, January 16 a trough of low pressure with warm and humid air is forecast to lie over the North Island and is expected to bring rain or showers to many areas.

There is low confidence that rainfall amounts could reach warning criteria over parts of the North Island from Waikato across to Hawkes Bay, northwards.

Thunderstorms and localised downpours are also possible in these areas.

On Wednesday, a trough of low pressure with warm and humid air is forecast to lie over central New Zealand, bringing rain or showers to central and northern parts of the country.

At this stage, there is minimal risk of severe weather over New Zealand, however isolated afternoon and evening thunderstorms are possible over central and northern areas, with locally heavy rain.

Thursday's and Friday's weather forecast is similar to Wednesday's with the trough of low pressure continuing to bring warm and humid air over the middle of the country. 

Rain and showers are likely with a minimal risk of associated severe weather, but isolated afternoon and evening thunderstorms are possible, with locally heavy rain.

Meanwhile, on Friday, a front is forecast to approach Fiordland from the west, with low confidence of warning amounts of northerly rain affecting the area.