A heat blast incoming early next week from Australia could force temperatures up into the mid-30s.
"As we head into next week heat from both Australia and the sub-tropics will merge with a nor'wester to push temperatures up to the mid-30s in some inland, eastern, areas," WeatherWatch says.
"By Tuesday most places are dry, high pressure dominating the North Island but we've got these warm winds coming in. So they're sub-tropical, coming down around this big high, turning around, getting caught up in that Australian heat as well.
"It's both tropical and subtropical heat mixing with Australian heat and coming in as a nor'wester which is even warmer for us as well."
So how hot will it get?
"It's possible that temps could reach the mid-30s, particularly in the east of both islands! For now, that includes Canterbury, Marlborough, Hawke's Bay, Gisborne, and Bay of Plenty," NIWA says.
"It may be cool now, but it won't stay that way. We are near our annual peak in air and sea temperatures."