Australian Open officials have pushed back the start time of play on day two of qualifying in the hope that smoke from the Victorian bushfires hanging over Melbourne clears.
The first matches on court today are now scheduled for midday, two hours later than the original start of 10am local time.
Conditions at Melbourne Park aren't forecast to improve until late on Wednesday after they plagued the opening day's play with organisers heavily criticised for allowing matches to proceed.
A number of players complained yesterday, including Australian Bernard Tomic, who sought medical treatment during his first round loss when he struggled to breathe.
Slovenia's Dalila Jakupovic feared she would pass out before retiring from her match when she collapsed to her knees with a coughing fit.
Health authorities expect the air quality to bounce between the "very poor to hazardous range" until at least Wednesday afternoon, with a top temperature of 34C before a late change that's set to bring rain.
Tennis Australia said it will continue to work with its medical team, the Bureau of Meterology and Environment Protection Authority Victoria scientists when making decisions about whether it's safe to play.
TA said it has installed measuring devices on-site for air quality, with play cleared to continue during the opening round of qualifying.
Qualifying top seed Dennis Novak from Austria will be in action against German Dustin Brown, while a number of local hopes take to the court on day two.
Among the Australian women, Kaylah McPhee will face Belarussian Greet Minnen while Jamie Fourlis meets Fang Yin Xun from China.
Olivia Rogowska and Storm Standers are also scheduled for first-round action.
In the men's draw, Akira Santillan will play Frenchman Quentin Halys while Sydney teen Rinky Hijikata has a tough first-up encounter against second-seeded Swiss Henri Laaksonen.
Australia is already guaranteed 18 players in the singles main draws, led by women's world No.1 Ashleigh Barty, with play getting underway on Monday.