Australian Open qualifying was disrupted for a second successive day due to poor air quality as smoke from bushfires continued to blanket Melbourne in an acrid haze on Wednesday.
Organisers said practice had been suspended at Melbourne Park until 1100 am (0000 GMT) and qualifiers would not get underway until 1300.
Play and practice at regional tournaments in Traralgon and Bendigo, along with a junior event at Royal Park in Melbourne, had also been suspended, governing body Tennis Australia said in a statement.
"Conditions at Melbourne Park are being constantly monitored and further decisions will be made using the onsite data and in close consultation with our medical team, the Bureau of Meteorology and scientists from EPA Victoria," TA said.
Organizers delayed qualifying for more than an hour on Tuesday due to the poor air quality but were criticized by players for allowing it to resume.
Slovenia's Dalila Jakupovic was forced to retire after suffering a coughing fit in the second set of her match and condemned tournament organizers for allowing play to go ahead.
Air quality is expected to improve later on Wednesday when rain showers are forecast but the weather is likely to cause further delays to the schedule.
Australia is experiencing one of its worst bushfire seasons on record, with fires burning for months and claiming the lives of 28 people, destroying more than 2,500 homes and razing forests and farmland the size of Bulgaria.
Bushfire smoke has affected a number of elite sporting competitions involving soccer, rugby league and cricket, and the pollution has raised safety fears for players at tennis's first Grand Slam of the year, which starts on Monday.