Nelson west of Motueka and Buller are also forecast to have periods of heavy rain, with thunderstorms at times. Rain is expected to accumulate to 90 to 110mm about the ranges and 60 to 90mm near the coast. This warning is in place until 6am tomorrow.
Heavy rain can cause flooding, poor visibility on the road and land slips so keep updated if you are within the warning areas.
There is a possibility that rainfall accumulations could meet warning criteria in northern Westland, Nelson from Motueka eastwards, Marlborough from Richmond Range to the Sounds, Tongariro National Park, and the eastern ranges of Bay of Plenty today and early Tuesday.
People should be aware there is also a risk of thunderstorms for some regions in the coming days.
There is a high risk of thunderstorms for Buller, western Nelson and Taranaki with the possibility these thunderstorms could produce a localised small tornado or waterspout.
For northern areas of the North Island from Northland to Waitomo and Taumarunui, also Kāpiti Coast, Wellington, the Marlborough Sounds, eastern Nelson, and Westland north of Hokitika there is a moderate risk of thunderstorms from this afternoon, while for the Bay of Plenty the risk increases from low this afternoon to moderate in the evening.
The rest of the week isn't looking much better, with an associated front forecast to move eastwards across central and northern New Zealand during Wednesday and Thursday, delivering rain and strong northwesterly winds to these areas.
New snow is likely about the North Island mountains and Southern Alps this week too.
A cool southerly flow is expected to spread over the South Island during Wednesday and Thursday, bringing periods of rain, and snow to the ranges of Southland, Otago, Canterbury and Marlborough.
Although this is good news for skiers, folk planning on travelling over the higher passes will need to keep an eye on forecasts.
However, look for gradually improving weather over the weekend and early next week as high pressure slides across from the Tasman Sea.
