All of the early scheduled matches on the outside courts at Melbourne Park got under way on time while several matches previously suspended due to the poor air quality or the rainfall were rescheduled to resume play later on Thursday.

Organisers have been heavily criticised over the last two days by players attempting to make the main draw of the season opening Grand Slam for continuing to play matches despite the poor air quality from bushfires.

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Australia is experiencing one of its worst bushfire seasons on record, with fires burning for months and killing 28 people, destroying more than 2,500 homes and razing forests and farmland the size of Bulgaria.

Several players, including former top-five women's player Eugenie Bouchard said they found it difficult to breathe during matches.

Slovenia's Dalila Jakupovic was forced to retire after suffering a coughing fit in the second set of her match on Tuesday and condemned tournament organisers for allowing play to go ahead.

Tennis Australia (TA) said earlier this week their decisions about whether conditions were fit for play were based on on-site data and in consultation with medical staff, weather forecasters and government scientists.

Bushfire smoke has affected a number of Australia's elite sporting competitions including soccer, rugby league and cricket.

Australia's Bureau of Meteorology forecast a maximum temperature of 19 Celsius (66.2 Fahrenheit) for Melbourne on Thursday with a slight chance of rain and the smoke haze improving.

TA, meanwhile, said in a statement on Thursday that a fundraising 'Rally for Relief' event held under the roof on Rod Laver Arena on Wednesday, had raised more than A$4.8 million for bushfire relief funds.

"We hope to raise millions of dollars throughout the summer of tennis and (this) is just the start," Australian Open tournament organiser Craig Tiley said in a statement.

The Australian Open runs from Jan. 20-Feb. 2.

(Reporting by Greg Stutchbury; Editing by Michael Perry)

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