Heavy falls are forecast for much of the North Island at times today, meanwhile the South Island is in for a mostly fine day.
Auckland is set for a day of rain, possibly heavy with hail at times, turning to showers by the evening and a high of 19C.
The NZ Transport Agency was warning motorists to plan ahead and use the organisation's journey planner to see travel times.
Hotspots included State Highway 1 northbound near Takanini today from 10am to 9pm.
There is also a moderate risk of thunderstorms about western Nelson and Kahurangi National Park, and also Taranaki and coastal parts of Waitomo and Waikato to midday.
These thunderstorms could produce heavy rain of 10 to 25mm per hour and small hail.
Later in the morning there is also a moderate risk of thunderstorms about eastern Bay of Plenty.
The wretched road conditions come as one person died in a single-car crash near Huntly yesterday about 8.35pm.
The person died at the scene of the crash on Hakarimata Rd, while the other occupant of the car had minor injuries.
The death was the first for the Easter holiday period this year. The holiday period officially ends at 6am on Tuesday. Last year seven people died over Easter.
The low over the North Island today would move east on Tuesday while a weak front moved onto the lower South Island from the southwest.
Mostly fine weather is forecast across most of the country for Wednesday before another weak front arrives on Thursday and moves up the South Island.
On Friday an active front would move onto the lower South Island from the Tasman Sea, bringing heavy northerly rain.
Today's weather
Whangārei A few showers, turning to rain for a while in the afternoon with heavy falls possible. Northwesterlies. 21C high, 10C overnight.
Auckland Rain, possibly heavy with hail at times, turning to showers by evening. Northerlies, dying out in the evening. 19C high, 11C overnight.
Hamilton Rain, turning to showers in the afternoon. Northerlies dying out afternoon. 18C high, 8C overnight.
Tauranga Rain, chance heavy, easing by evening, as northerlies die out. 19C high, 12C overnight.
New Plymouth Morning rain, heavy and possibly thundery, easing to a few showers afternoon. Northerlies dying out evening. 18C high, 10C overnight.
Napier Rain developing morning, chance heavy, easing evening. Northeasterlies. 19C high, 11C overnight.
Whanganui Occasional showers, clearing by evening. Southeasterlies. 19C high, 9C overnight.
Wellington A rainy morning then the odd shower. Southerlies. 17C high, 12C overnight.
Nelson Periods of rain, easing evening. Southeasterlies. 18C high, 11C overnight.
Christchurch Mostly cloudy, light rain clearing afternoon. Southerly dying out. 16C high, 8C overnight.
Dunedin Morning and evening cloud or fog, afternoon fine spells. Light winds. 15C high, 9C overnight.
