But while the rain is likely to ease today, the Waikato and Whanganui Rivers will continue to rise because of "runoff" from the downpours.
Wanganui was still bracing itself as authorities warned the rising Whanganui River could peak at its highest level in more than a decade.
The predicted river levels would be the highest since October 1998.
Wanganui District Council said the river levels had the potential to threaten the Kowhai Park stopbanks and a number of homes on Anzac Parade in the city.
"If you think of the Central Plateau it's a bit like the roof of your house - the rain will fall over it and then run down either side, in this case to the north or south. So we're going to see significant runoff into both the Waikato River, flowing northwards into Waikato - and the Whanganui River, flowing southwards into Wanganui city," said Weather Watch's head analyst, Philip Duncan.
Both rivers would continue to rise over the next 12 to 36 hours and residents and farmers along them should be monitoring local council websites for live data and information and special local Civil Defence messages, Mr Duncan said.
Some Nelson homeowners were forced to sandbag their properties while Westport was isolated because of severe flooding on State Highway 67 from Westport to Greymouth.
Other roads around the central North Island were closed yesterday, including State Highway 3 north of the Awakino Hotel after a slip blocked both lanes.
The MetService said a large high was expected to move onto New Zealand during today, drying out the areas most affected by the deluge.
The weather service's spokesman, Daniel Corbett, said the winter high would be similar to others at this time of year - there could be some cloud at times along with some fine blue-sky days.
Clear skies and light winds at night could bring frost and perhaps some patchy fog in sheltered places too.
The mostly dry and settled spell should be with us for most of the week and perhaps into the weekend, Mr Corbett said.
The National Institute of Weather and Atmospheric Research's outlook for July through to September has predicted a drier winter than usual for some areas.
New Zealand Transport Agency said the only highway which remained closed due to a slip was State Highway 73 from Springfield to Arthurs Pass. A report on the road's condition was expected by 9am today.
State Highway 3 from Awakino Tunnel to Awakino Township and State Highway 2 at Waioeka Gorge had both reopened after slips earlier closed them.
THE BAD
* At least five roads closed by flooding or slips.
* Some Nelson homeowners forced to sandbag properties.
* 250mm of rain on Mt Taranaki and 130 to 180mm of rain in the Tararua Ranges.
* Waikato and Whanganui Rivers are continuing to rise.
THE GOOD
* A large high will move over the country today, bringing settled weather.
* Seasonal temperatures are likely to be near average overall.
* In the west and south of the South Island, average or above average temperatures are likely.
* Late winter rainfall totals are likely to be normal or below normal in South Island regions and in the east of the North Island.
