MetService is warning that a slow-moving front will continue to deliver significant amounts of rain to already saturated northern and western parts of the North Island and the upper South Island through the weekend and beyond.

Heavy rain in the North Island eases from Friday morning, and the focus of heavy rain turns to the upper South Island.

Northland, Waitomo, Taranaki, Tongariro National Park, Horowhenua, Kapiti, and Wellington are currently under Orange Heavy Rain warnings.

'This large amount of rain falling on already sodden ground has seen surface flooding in Taranaki, Bay of Plenty and Northland, and other areas are likely to see the same, along with slips,” says MetService meteorologist Andrew James.

Nelson and northern Marlborough came under Orange Heavy Rain Warning overnight as the front sinks south.

An extremely large amount of rain is forecast for the western Tasman Ranges, with 350-450mm of rain predicted in a 42 hour period up to midnight Saturday.

'These areas have seen a lot of rain recently. Further rain could cause significant impacts –think rising rivers, slips and surface flooding, and people are urged to stay up to date in case these warnings are upgraded.

'The system is slow moving because a large high-pressure system to the east stops the subtropical rainband from moving on. Rain sticks around through the weekend and into early next week but snakes back and forth over the western parts of both islands, so the heaviest rain comes and goes.”

Wet weather looks set to continue through the weekend, with the bullseye of the wettest weather shifting away from central New Zealand towards the southern stretch of the South Island west coast on Sunday.

The tropical air delivering all this rain also brings warm and humid conditions, with much of the country experiencing unusually warm May temperatures.

Several spots across the motu/country have even had their warmest May temperatures on record.

These include Auckland, Hamilton, Whanganui and Queenstown, while Wellington Airport recorded its second warmest minimum temperature for May with 17.6°C on Wednesday.