A severe weather warning has been issued for the Bay of Plenty as heavy rain approaches the region.

The MetService has issued the warning this morning. The warning is also in place for southern Westland and northern Gisborne.

'A front approaching from the Tasman Sea is expected to become slow-moving over southern Westland this afternoon, while a second front approaching from the south moves over Fiordland this evening.

'These two features are expected to bring rain to the southwest of the South Island.”

Meanwhile, a low and associated front over the north Tasman Sea are slowly approaching the north of the country.

The weather organisation says the low should lie to the west of the upper North Island during Thursday, with its associated front crossing the North Island during Thursday and early Friday.

The front is preceded by a strong moist northeasterly flow, and is expected to bring a period of northeast gales and rain to northern New Zealand.

'The heaviest falls are likely in Westland south of the glaciers, and Bay of Plenty and northern Gisborne, where 80 to 110mm of rain may accumulate in a 15 to 18 hour period.

'People in these areas, especially trampers, are advised to look out for rapidly rising rivers and streams. Slips and surface flooding are also possible.”