The centre of the low is expected to be about 250km east northeast of Auckland at 7pm.
Heavy rain warnings are in place for Northland, Great Barrier Island, Coromandel Peninsula and Gisborne.
Rain could also be heavy in Auckland (mainly north of Orewa), Waikato, western Bay of Plenty and the eastern ranges, and northern Hawke's Bay.
Severe gales with gusts to 120km/h are forecast. MetService says the strongest winds are expected in Northland, Auckland (mainly about Great Barrier Island and the Hauraki Gulf), Coromandel Peninsula, Bay of Plenty (mainly about the ranges) and Gisborne.
Heavy rain is lashing the upper North Island as ex-Cyclone Hola brushes past the upper North Island.
Kerikeri had already been battered with 26.2mm of rain during and Auckland had 10.4mm, according to the Metservice, but it was the Bay of Plenty which appeared to be bearing the brunt of the storm.
Since 4pm, the Metservice reported 29.8mm of rain had fallen in Tauranga with almost 10mm still expected to come before midnight.
But the rain did not stop surfers from making the most of the swell Hola brought with her.
About 80 surfers braved the elements at Mt Maunganui to catch waves estimated to be about 2m high.
This afternoon Weatherwatch forecaster Philip Duncan said as Hola devolved into an extra tropical storm the worst of the weather would remain offshore away from most people and properties.
"Gale-force winds remain just east of Auckland and Northland regions but winds are fairly light over land.
"More than half of Hola is at sea with perhaps around 40 per cent brushing New Zealand today, tonight and before dawn on Tuesday," WeatherWatch head forecaster Phil Duncan said.
Winds would pick up in the south and southwest of the upper North Island as Hola's centre moved towards the East Cape.
"These winds may be strong and perhaps even gale force in some exposed areas - but significantly damaging winds are no longer in our forecast for these regions."
Rain bands, with a mix of moderate to light falls, now lay over much of Northland, Auckland and Coromandel Peninsula and parts of Waikato and Bay of Plenty.
"Bay of Plenty, Gisborne, and Hawke's Bay, the main rainfall period is from later this afternoon to late tonight/very early Tuesday morning.
"Heavy rainfall exceeding 30mm/h is possible at its maximum phase, otherwise light to moderate falls are also expected," Duncan said.
Hola could weaken even further due to interacting with the upper North Island ranges, which are breaking up the air and moisture flows feeding back into the storm centre.
MetService currently has heavy rain warnings for Northland, Great Barrier Island, Coromandel Peninsula and Gisborne.
Gisborne's warning stayed in place the longest, from 3pm today to 6am Tuesday.
Strong wind warnings of up to 120km/h were in place for the same previously mentioned areas as well as Bay of Plenty and Rotorua.
Air New Zealand cancelled flights in Whangarei and Kerikeri this morning.
"Three one-way services between Kerikeri and Auckland and three one-way services between Whangarei and Auckland have been cancelled due to weather this morning," a spokeswoman said.
"Customers booked to travel today are advised to keep an eye on the arrivals and departures page of Air New Zealand's website for up to date flight information."
It has been a particularly "active" cyclone season, and Kiwis could expect another one or two before the season ends in April.
Another system is forming in the Coral Sea, just south of the Solomon Islands.
MetService meteorologist Tom Adams said it could be named Tropical Cyclone Linda sometime in the next few days.
"There is a lot of variation at the moment. There is a chance it could affect New Zealand, but significant chance it could affect Australia.
"But at the moment it could go anywhere. We need to deal with [Hola] first."