A slew of weather warnings and watches have been issued as heavy rain and severe gale force winds are set to hit many parts of the country.
Twenty-two severe weather warnings and watches have been issued for a low-pressure system that is expected to affect much of the country during the first half of this week.
The MetService warnings come as NIWA says an "atmospheric river" is expected to bear down on the country.
"Rain will begin to impact the North Island on Monday, but the heaviest rain is expected on Tuesday (including in the upper South Island)," NIWA said in an update on its Facebook page on Sunday night.
"Be careful around streams and rivers on Tuesday, as intense rainfall could cause flow rates to increase rapidly."
Here are all the warnings and watches in place issued by MetService.
Coromandel Peninsula
MetService has issued a heavy rain warning in the Coromandel from 5pm on Monday until 11am Tuesday with up to 110mm of rain, especially about the ranges.
Peak rates of rain could hit up to 25mm/h on Tuesday.
Bay of Plenty
Heavy rain is set to hit the area of Bay of Plenty including Rotorua from 8pm on Monday until 3pm on Tuesday, with rainfall expected to be up to 120mm.
Gisborne
MetService issued a heavy rain warning for Gisborne and north of Tolaga Bay from 4pm on Monday until 4pm Tuesday, the rainfall is set to get to 140mm with a peak rate of 30mm/h on Tuesday.
A heavy rain watch has also been put in place for the south of Tolaga Bay.
Marlborough
MetService warned Marlborough will be impacted by a large rainfall of up to 140mm throughout the Kaikoura Coast and ranges and up to 100mm of rainfall elsewhere.
Northland
The forecaster issued a rain watch for Northland, expected to last around 17 hours from 2pm on Monday until 7am on Tuesday.
Waikato, Taupō, Taihape
Heavy rain is due to hit the Waikato, Taupō and Taihape for 13 hours from 10pm on Monday until 11am on Tuesday.
Hawke's Bay
MetService warned Hawke's Bay will be hit with a period of rain for 16 hours from 11pm Monday until 3pm on Tuesday.
It also warned of a strong wind watch south of Hastings, Wairarapa including the Tararua District, from 5am until 2pm on Tuesday.
Tasman
Heavy rain is forecast for Tasman and west of Motueka, with 16 hours of rain set to hit from 1am until 5pm on Tuesday.
A strong wind watch has also been issued for Tasman and Buller, with an east to southeast winds potentially approaching severe gales in exposed places.
MetService also reported there is a possibility of snow throughout the lower South Island.
"In addition, rain is expected to fall as snow down to 400 metres in Canterbury and 500 metres in Otago on Tuesday, with warning amounts of snow possible above 600 metres."
The snowfall is expected to hit from early Tuesday morning until early Wednesday morning.
Canterbury
The forecaster has issued a strong wind watch throughout Christchurch including Banks Peninsula from 8pm Tuesday until 8am Wednesday.
A heavy snow watch has also been put in place that will impact Canterbury's High Country with snow expected to fall down to 400 metres.
Central Otago
Heavy snowfall is expected to hit parts of Otago including Queenstown Lakes with MetService warning up to a possibility of 600 metres.
The snow is forecasted for 14 hours from 11am on Tuesday until 1am Wednesday.
MetService warned that the heavy rain may cause streams and rivers to rise rapidly. Surface flooding and slips are also possible and driving conditions may be hazardous.
The heavy rain is expected to hit those parts of the country from late Monday afternoon until early Tuesday afternoon.
MetService said people need to keep up with the weather updates as more orange heavy rain warnings are likely to be issued throughout New Zealand.
"This is a significant event. People are advised to keep up to date with the latest forecasts as parts of these watches will likely be upgraded to orange warnings, or more areas are added."
