MetService has issued a severe weather outlook for the week ahead.

"A front is expected to move slowly north over the South Island on Tuesday, Wednesday and Thursday bringing rain to many South Island areas," says a MetService spokesperson.

The weather organisation has issued updates on rain expected across the South Island.

"On Tuesday there is a low confidence in warning amounts of rain for Fiordland. On Wednesday there is a low confidence in warning amounts of rain for Fiordland and the south of Westland.

"On Thursday there is a low confidence in warning amounts of rain for Westland and Buller."

MetService says an intense subtropical low is expected to move southeast just north of the North Island on Friday, bringing heavy rain and gales to many North Island areas.

"At this stage there is a moderate confidence in warning amounts of rain and severe gales for Gisborne, Bay of Plenty, Rotorua, Coromandel, Auckland and Northland.

"People are advised to keep up to date with the latest forecasts since the heavy rain and strong winds could bring significant impacts."