Stormy weather in Christchurch has caused roads to flood, and drivers in the northern half of the North Island are being warned of slippery roads in the first rainfall for more than a fortnight.
In Christchurch, Lincoln Rd and State Highway 76 at Brougham St have been flooded, and other roads may be affected, the city's transport operations centre says.
Rain moved over much of the North Island today, dropping about 15mm of rain in areas from Wairarapa to Auckland.
The Wellington region recorded 10-25mm, MetService said, with some surface flooding reported.
In the South Island, wet weather was becoming confined to the east of the South Island as a weak ridge started to build in the lower half of the country.
Police urged motorists to slow down on roads in the Waikato through to Auckland and Northland, where there could be conditions described as 'summer ice'.
This is when dust, oil and other materials build up in dry spells on the road surface, making it greasy when it rains - with the greatest risk shortly after the rain starts.
Even a little rain after several days of dry weather can trigger these conditions, NZTA says.
MetService meteorologist Mark Bowe said many areas of the South Island would be fine and dry tomorrow.
"It will be a country of two halves on Tuesday with the ridge over the South Island keeping the wet weather confined to the North Island."
Fine breaks and dry weather continue for South Islanders on Wednesday, and conditions over the North Island begin to ease with the only shower activity confined to the eastern coast by Wednesday evening.
Thursday will see a weak front move onto the lower South Island bringing some periods of rain. The low to the northeast of the North Island moves away on Thursday, leaving one or two showers over the central and eastern parts of the North Island as it departs.
On Friday a southwest flow blankets the country with the chance of a shower or two to finish off the week.
NZTA advice in 'summer ice' conditions:
- Keep speeds down on wet roads after a long dry period
- Take extra care on curves
- Increase following distance from vehicles in front of you
- Brake and steer gently
- Allow extra travel time