"While we can't travel to many tropical places at the moment, the air is coming to us instead and so it does feel almost Fiji-like in Auckland at the moment," Fedaeff said.
Little said people should expect conditions to be similar during the evenings.
For the next five nights, minimum temperatures of 21 and 22 are forecast for Auckland - which is just six degrees less than the city's high of 28 today.
Hamilton and Kaitaia had similar forecasts.
Hamilton would see highs between 25 and 28 degrees during the week and lows of 20 and 21 while temperatures in Kaitaia will vary between 24 and 28 degrees with lows between 21 and 23.
"So it's not only going to be uncomfortably muggy during the day but in the evenings as well," said Little.
Another tropical plume is headed for the West Coast tomorrow and a tropical disturbance that will bring rain, humidity and wind is expected to hit the North Island later this week, said Fedaeff.
"Basically anytime you hear the word tropical in the name expect more of that humid type of weather to continue," she said.
Tips to beat the heat
As the conditions settle in, Little has shared some tips on how to beat the heat and humidity:
1. Ditch the duvet, stick with a single-sheet.
"If you don't have air conditioning it's really going to be a single sheet kind of sleeping condition, no need for duvets."
2. Avoid exercising during the hottest parts of the day.
"People exercising need to try and avoid the middle of the day and the afternoon where it's going to be extra hot."
3. Stay hydrated.
"It's certainly important to drink a lot of water and to not to get dehydrated."
4. Utilise air-con if you have it.
"If you've got air conditioning, you'll certainly be able to benefit from the cooling it can provide."