Tuesday and Wednesday brought record average temperatures, reaching 41.9C (107.4F), while bushfires continued to rage in New South Wales.

The heat is expected to rise again on Friday with a peak of 45C in Melbourne.

Coach Gary Stead says New Zealand will spend Friday resting before playing in a one-day match on Sunday.

"The squad will train at the MCG on Saturday morning in much cooler conditions before batting first in a full-day match against the Victoria XI on Sunday," he added.

New Zealand, who face Australia in the second Test on Boxing Day, lost the first of the three-match series in Perth by 296 runs.