Health officials are warning people to take extra care as rising temperatures continue to break records.
February may be heading for the hottest month on record as the temperature across the country is on average 2-3 degrees warmer than normal.
The higher temperatures have also been accompanied by higher humidity.
On February 6 the temperature reached 41.3degC in Timaru, a 125-year high, while Gisborne sweltered in 36.3degC heat on February 2, a 105-year high.
Many centres were reporting their warmest days on record and the Auckland Regional Public Health Service said it was timely to remind people to protect their health.
Clinical director Julia Peters said many people would not know of the health risks associated with the heat and high humidity.
``Hot summer weather can be a problem for the vulnerable such as the elderly, young children and those with medical conditions. The humid weather has already been disrupting sleep patterns,'' she said.
``The messages are common sense: stay out of the sun, if you can. Sit in the shade, drink lots of cool water, wear light-coloured, loose clothing. Keep your house as cool as possible to facilitate better sleep at night.
``We encourage people to check on elderly neighbours or family to make sure they're okay and drinking enough water in the heat,'' she said.
She said pets also suffered in the hot weather.
Tips on how to deal with the extreme heat and high humidity were on the website: www.arphs.govt.nz