Australia has just sweltered through at least five of its 10 warmest days on record, authorities estimate.
An extreme heatwave has afflicted the nation since Saturday, causing wildlife deaths, bushfires and a rise in hospital admissions.
Australia’s Bureau of Meteorology said preliminary readings showed daily national temperature highs of 40C (104F).
The town of Noona in New South Wales hit a night-time temperature of 35.9C.
Temperatures on Friday will soar above 42C in “broad areas”, the Bureau predicted.
Forecasters have compared conditions to the nation’s worst heatwave in 2013, where the mercury soared to 39C for seven consecutive days.
The hottest day on record for Australia is 7 January 2013, when the national average maximum temperature was 40.3C.