A low is set to approach New Zealand from the Tasman Sea on Monday, bringing with it heavy rain and strong winds.
"In the days ahead developing low pressure and a cold front out of Australia are heading our way with rain from the west and a temperature drop coming nationwide," WeatherWatch says.
"Showers and rain start to increase on the West Coast as of Sunday with heavy falls in the days ahead. 100 to 150mm of rain is possible.
"North to north-west winds increase further on Monday with gales increasing in central New Zealand (Cook Strait) and through alpine areas where severe gales may be possible."
Rain
MetService warns there's moderate confidence of warning amounts of rain in Fiordland, Westland and the headwaters of Otago and Canterbury lakes and rivers during Monday and Tuesday.
On Tuesday, there is also moderate confidence of warning amounts of rain around the ranges of Buller, Nelson, western and northern parts of Marlborough, the Tararua Range, northern Taranaki, Taumarunui and Taihape.
There is low confidence of warning amounts of rain about the eastern ranges of Bay of Plenty on Tuesday.
Winds
There is also a moderate confidence that north to northwest winds will reach severe gale in exposed parts of Fiordland, Southland and Otago - except Dunedin and north Otago - on Monday.
There is also moderate confidence of northwesterlies rising to severe gale in exposed parts of Canterbury High Country, Marlborough, Wellington and Wairarapa during Monday and Tuesday.
On Wednesday, there is low confidence of southwest winds reaching severe gale in exposed coastal parts of Westland and Buller, northwest Nelson and in the west of the North Island from Northland, Auckland, Coromandel Peninsula to Taranaki.
