South Island residents will get a taste of summer later this week, with temperatures likely to be 15 degrees warmer than usual for this time of the year.
A flow across the Tasman Sea could bring near record temperatures to inland parts of Otago, Southland and Canterbury on Thursday.
NIWA meteorologist Ben Noll said there will be two consecutive days of scorching weather.
"Two consecutive days with well above average temperatures across the South Island and then some moving to the lower North Island as we go into Friday."
The heat is then set to creep towards northern Canterbury, Tasman and Marlborough by Friday.
Noll said the temperatures could nudge record levels.
"We're talking temperatures that could challenge records in some places, well into the twenties and perhaps New Zealand's first 30 degree reading since April."
LISTEN ABOVE AS BEN NOLL TALKS TO LARRY WILLIAMS