Australian Open officials have applied the extreme heat policy for the first time this week at Melbourne Park.
After temperatures consistently above 40 degrees in Melbourne since Tuesday, tournament referee Wayne McKewen opted to enforce the extreme heat rule on Thursday.
The ruling means current matches being played will be suspended at the conclusion of the set and no scheduled matches on outside courts will start until conditions improve.
The announcement will come as a relief to the players, with Australian star Samantha Stosur on Wednesday night urging Open officials to apply some common sense if forecast temperatures of 44 degrees hit Melbourne Park on Thursday.
"If it gets to 44, that is certainly another step up,'' Stosur said.