The Bay of Plenty, Taranaki, Waikato, Northland and the top of the South Island also have MetService weather warnings and watches in place for Friday.
Officials across the top of the South Island and the West Coast were also monitoring heavy rainfall into the night - brought to our shores by a deep low crossing the Tasman Sea.
All Gulf Harbour ferries have been cancelled, with replacement buses running and number of power cuts have been reported around Auckland.
It follows a night of heavy rain that pushed in from Northland.
Some areas of Northland received more than 100mm overnight with more to come this morning - but Civil Defence says no major road closures or serious flooding have been reported.
The top of the South Island and the West Coast had heavy rainfall overnight, with a deep low crossing the Tasman Sea.
Buller Mayor Jamie Cleine said an emergency operations centre had been set up in Westport.
MetService meteorologist John Laws told Morning Report a band of warm air was driving the rain and moisture but the "atmospheric river" was pulling away to the east.
That meant the weather was moving fast across the country and would begin to clear late this evening.
Heavy rain warnings and watches are still in effect at the top of both main islands this morning.
Laws told Morning Report it has been a very wet start today in Auckland with more rain in one night than for the whole of March.
"At the moment the rain is pulling away toward the east so probably the heaviest rainfall in the next few hours across Auckland.
"But it is going to be wet roads and with the rainfall around this morning do take extra care and extra caution on those roads."
However, Laws says the rain is moving east toward the Bay of Plenty and severe weather warnings will remain in the Eastern Bay of Plenty until early Saturday.
He says the rain will ease in Tasman later tonight as well.
MetService lead forecaster Alain Baillie said overnight the most rain was seen in Nelson and Tasman where 200mm fell.
NZ Transport Agency Waka Kotahi says all state highways are open in the top of the South Island this morning following the deluge overnight.
There has been some surface flooding on State Highway 65 between Springs Junction and Murchison, but the route is open to traffic.
Drivers still need to exercise caution on the roads, particularly during peak travel times this morning, NZTA says.
Heavy rain advisories are still in places throughout Marlborough, Tasman and Buller though many are expected to end by early this afternoon.
In the North Island, the Bay of Plenty, Coromandel, Northland and the Tararua Ranges will have warnings in place throughout today for most.
In Auckland, Some power outages are being reported in parts of Remuera, Piha and Karekare.
Vector's online map shows an unplanned outage in parts of Remuera and Greenlane.
A network or equipment fault has also caused an outage in the Piha, Karekare area.
The same type of fault is said to be behind a third outage in Glenfield on the North Shore.
Vector says it should be restored between 3pm to 4pm today.
