Melbourne has recorded its hottest February day ever. The temperature hit 46 degrees in the middle of Saturday afternoon.
The weather bureau in Melbourne says it will continue to rise until a cool change comes through later on Saturday.
New Zealand's Metservice says New Zealand will also experience sweltering temperatures during the weekend, as the hot weather heads across the Tasman Sea.
It won't be quite as hot as Australia, because the sea will cool most of the hot air as it passes over, but Canterbury can still expect temperatures in the mid-to-high 30s.
Fires rage across Victoria and NSW
Meanwhile, three homes have been destroyed in Australia and many more are under threat across Victoria and New South Wales as thousands of firefighters battle dozens of bushfires.
Six major fire fronts are raging across Victoria; residents have described smoke so thick it blotted out the sun.
In the Singleton area of northern New South Wales, arson is suspected as the cause of three bushfires that have linked up and are burning out of control, consuming terrain at an alarming rate.
More than a thousand hectares of countryside have burned since Friday night as the fires, moving rapidly in hot and windy conditions, joined as one.