Canada's Frank Dancevic required medical attention after fainting in his first-round match and said it was "inhumane" to allow players to compete in such testing conditions.
Britain's Andy Murray says the incident may damage the event's reputation.
"It doesn't look good for the sport when people are collapsing," he said.
"Most of the players are conditioned well enough to last in that weather but doing it for three or four hours is tough to recover from."
The high temperatures resulted in a number of incidents at Melbourne Park on Tuesday:
- Former women's world number one Caroline Wozniacki's plastic water bottle melted on court
- Defending women's champion Victoria Azarenka described the heat like "dancing in a frying pan"
- 2008 finalist Jo-Wilfried Tsonga's shoes softened in the high temperatures
- Ballboys and ballgirls have their shifts reduced from 1hr to 45mins to stop them overheating
- Serbia's Jelena Jankovic, who won the Wimbledon mixed doubles title in 2007, burnt her backside on an uncovered seat