The country is set for a brief respite of cooler weather this weekend as New Zealand enters the "peak" of the heat wave today.
Temperatures in the South Island were cranked to the max yesterday, with Cheviot reaching 36.1C - New Zealand's warmest temperature this summer, Pukaki (Mt Cook) reached 34.8C, Hurunui 34.4C and Masterton got to 32.7C.
Niwa said Thursday would be the "peak" of the heat wave, and predicted temperatures could reach 37C in parts of north Canterbury.
Fine weather is on the cards for the Auckland region again today with a high of 27C, although there will be some cloud in the morning and evening, with easterly breezes.
MetService meteorologist Hannah Moes said today's top main centres were forecast to be Blenheim in the South Island on 34C, and Masterton in the North Island on 33C. But many more spots were tipped to top 30C, a trend the country has experienced since the heat began on Sunday.
"Today is looking very similar to the past few days, apart from some cloud in the morning and at night it is looking fine for most places," Moes said.
The country's eastern centres were looking to be the pick of the bunch again, with high temperatures boosted by the foehn effect as the air mass passed over the country's central mountain ranges.
The exceptions to the fine weather were gale northerlies forecast about Fiordland and strengthening westerlies in central New Zealand.
Last night was another sweltering one for Auckland, with the mercury hovering around 20C before dipping to 18C about 6am.
MetService meteorologist Lisa Murray said some respite from the heat was coming for parts of the country in the form of a punchy southern system.
"We are still under this ridge of high pressure, what we are seeing is a slight increase in winds," she told the Herald.
"We've been seeing these sea breezes in the afternoons cooling things down, sometimes by as much as 10 degrees.
"What we're going to see now is as the new front approaches the winds will pick up over Fiordland and other places gradually and then across the country."
The front is expected to slide northeast across the South Island and the lower North Island which will bring gale-force winds to many areas tomorrow.
But the run of warm weather isn't over, another ridge of high pressure is expected to arrive over the country on Saturday and Sunday.
Since the start of the week there have been at least three cases of children being locked in vehicles in sweltering conditions.
Police advised members of the public who see children in distress to contact emergency services immediately.
St John ambulance crews have also been kept on their toes during the week with a number of heat-related incidents since Saturday.
Assistant director of operations for St John Tony Devanney advised people to be careful in the hot weather by avoiding the sun as much as possible.
"Those with existing health conditions and illnesses also need to take special care," he said.
Meanwhile, train services in Wellington crashed on Tuesday evening following record-high temperatures which shut down the network.
About 8000 commuters had to find another way home after the outage affected the Hutt and Johnsonville lines.
Temperatures in the city passed 30C around 4pm, including a record-high 30.3C in Kelburn.
Elsewhere, Auckland Zoo residents Burma and Anjalee, two Asian elephants, were treated to wheelie-bin sized ice blocks to cool them down.
According to Watercare, Auckland residents drank or used 524 million litres of water on Tuesday which is 20 million litres more than the previous record.
"As the mercury rose, so did consumption," it said in a statement.
"Watercare worked to supply more treated water, so that no taps ran dry: producing 530 million litres ―six million litres ahead of demand."
Fine apart from morning and evening cloud. Easterly breezes. 25C high, 18C overnight.
Auckland Fine and warm, but some cloud morning and night. Easterly breezes. 27C high, 18C overnight.
Hamilton Fine and warm, but some cloud morning and night. Light winds. 30C high, 16C overnight.
Tauranga Fine apart from morning and evening cloud. Light winds. 25C high, 18C overnight.
Whanganui Fine with light winds, then some evening cloud. 28C high, 18C overnight.