Anyone out and about in parts of the South Island is being told to keep their shoes on, as road surfaces hit sizzling temperatures of up to 62C.
The MetService said it had recorded the blistering temperatures in areas at the top of the South Island just after 3pm.
"It's over 62C on the tarmac inland from Blenheim. Bare feet NOT recommended,'' the MetService said.
Temperatures are starting to hit the 30s in the South Island this afternoon, with the North Island not far behind.
Today's current warmest temperature is being felt in Hurunui, in north Canterbury, which is sitting at 32.1C, while Masterton is at 31.9C and Mt Cook Aerodrome is at 31.7C.
Dunedin Airport is also clocking in a high 30.5C, Woodburn near Blenheim is at 30.4C and Alexandra is also 30.4C.
On the MetService's temperature graph on its website - which offers real-time conditions with the help of the public - Mt Isobel Place, in Hanmer Springs, recorded 36.2C at 3.30pm.
Ngawī, on the south coast of Wairarapa, is leading the temperatures for the North Island with 30.6C.
The main northern centres are slightly cooler, with Auckland at 26.1C, Wellington at 25.8C, Hamilton at 27.3C, Tauranga at 23.2C, Gisborne at 26.4C and Napier at 26C.
Earlier today forecasters predicted that today would be the "peak" of the heat wave, and temperatures could reach 37C in parts of North Canterbury, with many more spots tipped to top 30C.
Remember your pets and animals:
Those with pets and animals are being urged to remember them also during the heatwave - keeping livestock and pets well watered and providing good shelter for them.
The Ministry for Primary Industries has issued a statement calling on animal owners to remember their responsibilities during the heatwave.
MPI's national animal welfare co-ordinator, Dr Wayne Ricketts, said: "Basically, you've got to think of the things that you as a human would do during a heatwave - to get into shade with good ventilation and have plenty of water to drink.
"It's all commonsense stuff, yet every time we have a heatwave, MPI hears of animals being left without these things.''
Special attention needed to be given to vulnerable stock or pets, including those who had recently given birth.
"Owners should also take extra precautions for animals with bare skin, short coats or no pigment in their skin, as they are more susceptible to sunburn.''
The country has been experiencing unusually high temperatures since the heatwave began on Sunday.
If you are sick of the heat, there is hope, MetService is forecasting a front to bring rain to many parts of the South Island tomorrow - and a few showers about the North Island on Saturday.
This front will also be accompanied by cooler air, bringing temperatures back to average for this time of year this weekend, with some relief from warm and muggy overnight temperatures.
The front will also bring some severe weather with it, with Severe Weather Warnings issued this morning for strong wind in Canterbury High Country including the foothills, Otago, Fiordland and Southland. These will all occur early on Friday.
Although the warnings are focusing on the winds preceding the front, the southerly expected behind the front is worth noting as it will be briefly strong along the east coast of the South Island, and also central New Zealand.
"We could see some brief southerly gales behind the front with strong gusts all the way through to central New Zealand," said MetService meteorologist Kyle Lee.
There is also a heavy rain watch out for the west coast of the South Island for tomorrow morning.
With official heatwave conditions in store for quite a few areas today and tomorrow, the welcome news is that temperatures will cool slightly to more average temperatures for this time of year.
"Places like Blenheim are expected to peak at 33C on Friday ahead of the front, with the maximum temperature dropping to 21C on Saturday.
"More significantly the overnight temperatures are expected to drop for the country as well, which will make sleeping easier over the weekend," Lee said.
After the front has weakened away by the end of the weekend, a ridge of high pressure is set to dominate the weather again for the country leading in to next week.