Organisers suspended play at the Australian Open Thursday after temperatures hit 41.7 Celsius (107.1 Fahrenheit) on a third day of extreme heat.
Players will complete their current sets before a suspension of at least one hour, a spokeswoman said, while the roofs will be closed on the centre and second courts. (Related: Serena paranoid about the heat)
The tournament's opening days have been dominated with complaints over heat, with players falling dizzy, fainting and vomiting, and warnings of serious health problems. (Read: 'I thought I would die while playing')
Temperatures were forecast to reach 44 Celsius on Thursday and remain high on Friday before cooling sharply on Saturday.
America's Varvara Lepchenko was the latest victim on Thursday when she had her pulse and blood-pressure checked and was rubbed down with ice by staff during a medical time-out.
Temperatures had already reached 38 Celsius as play started at 11:00 am, with players shrouding themselves in ice packs and gulping drinks at the changeovers.