Despite the distance between the regions, both were hit by wet weather because they were in the west.
With the front now tracking eastwards, western areas would be the first to see clear skies.
Heavy rain was continuing in Marlborough, the lower North Island, Coromandel and Bay of Plenty.
In the eastern Far North between Kaeo and Kerikeri, swollen rivers have spilled over onto flood plains, closing roads and flooding farmland.
Northland Regional Council hydrologist Dale Hansen said some areas had received 75-125mm of rain by this morning, which came on top of 50-70mm of rain in previous days.
"When you put it in comparison with what Nelson has experienced recently, it's quite low with respect to that, but still a significant event for Northland in terms of the preceding wet weather in the last three or four days.''
The New Zealand Transport Agency said there was widespread surface flooding in the region and traffic was down to one lane in some places.
State highways 1 and 10 had to be closed at several points, including SH1 at the Rangiahua Bridge and SH10 near the community of Kaeo, but have since been reopened.
A heavy rain warning has been issued for the Bay of Plenty region, but there were no reports of weather-related issues so far.
In Auckland, minor surface flooding this morning caused traffic on the northern and northwestern motorways to slow to a crawl, while gusty winds prompted a warning to drivers to take care on the Harbour Bridge.
Light rain would ease tonight and clear overnight.
The Fire Service said it had been called to very few weather-related incidents in the North Island, including a fallen powerline in Northland and a toppled tree in Auckland.
In the waterlogged Nelson and Tasman regions, a brief respite this morning was followed by a burst of more heavy rain.
The regions received almost two months' worth of rain yesterday, with Civil Defence saying the totals were "well in excess'' of a one-in-100 year event.
There have been scores of slips throughout the region, including one that forced the evacuation of a Nelson apartment complex.
Civil Defence said river levels were now dropping but land was still heavily saturated.
Tasman police commander Superintendent Gary Knowles said emergency services had been working around the clock to tackle weather-related issues.
While flooding had abated slightly, the countless slips were causing a great deal of trouble and damage to property.
Mr Knowles said while emergency services were stretched, he believed staff were coping extremely well.
"This is a team effort and all of the agencies are working well together with a common sense of purpose.''
Evacuations continued all day, including 100 people from the Pohara Valley.
The army was unsuccessful in trying to reach a group of people trapped as a result of slips on Cable Bay Rd, but police were not concerned for their safety as they were getting assistance from the local community.
Residents in the Wood area of Nelson were asked to leave their homes for several hours this afternoon as the hillside behind began slipping.
Most have since returned, but some were unable to return because their houses were deluged with mud or close to the danger zone.
Two welfare centres have been set up in Richmond and Tahunanui to accommodate people displaced by the weather.
Mr Knowles said some roads have reopened, but one of the main arterial routes into the city, through Wakefield Quay and Rocks Rd, remained closed.
"We have some serious issues in that area as a result of landslides and the resulting damage to property and it is unsafe for people to use the road, be they driving, pedestrians or cyclists.''
Traffic was gridlocked leaving the city and motorists were urged to be patient and drive with extreme care.
People should stay off roads unless absolutely necessary, because waves from vehicles were damaging properties.
The weather has cut power and telephone lines in some areas.
Contractors were working to restore 300 phone connections around Britannia Heights, but up to 500 landlines in Tahunanui would remain out of action for a week due to a landslip.
Residents have been urged to conserve water.
The Fire Service attended 118 callouts overnight, involving nine brigades from the Nelson and Tasman area, and the army was brought in to assist.
Most of those involved helping people, evacuations and clearing fallen trees.
