Photo taken on Dec 21, 2019 shows smoke-covered Blue Mountain in New South Wales, Australia. (BAI XUEFEI / XINHUA)

SYDNEY - Thick bushfire smoke has delayed the first day of qualifiers at the Australian Open tennis tournament in Melbourne on Tuesday, with the toxic smog deemed too hazardous for athletes to play in.

"Practice was temporarily suspended this morning due to poor air quality," Tennis Australia said in a statement.

More smoke from the fires has come across overnight, and winds at the moment are very light, giving us smoke around even thicker than it was yesterday

Dean Stewart, Duty forecaster, Bureau of Meteorology

"As always the health and safety of our players, our staff and our fans is our priority."

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While qualifying matches are now set to get underway at 11:00 a.m. local time, Tennis Australia added that conditions onsite are constantly being monitored and that any further decisions will be made using onsite data in close consultation with medical specialists, the Bureau of Meteorology and scientists from Environmental Protection Agency Victoria.

Moving in from fires still burning in the East Gippsland region, Bureau of Meteorology's duty forecaster Dean Stewart told the Age Newspaper that the poor air quality is likely to stick around for at least 24 hours, which could throw the entire Australian Open tournament into chaos.

"More smoke from the fires has come across overnight, and winds at the moment are very light, giving us smoke around even thicker than it was yesterday," he said.

"There will be a south-westerly change coming through late in the day on Wednesday, which should help clear things out, and some shower and thunderstorm activity will develop."

So thick is the smoke that the Melbourne Metropolitan Fire Brigade has attended to 196 false alarms this morning.

READ MORE: Bushfire smoke threatens Australian Open in Melbourne

A number of public swimming pools have also shut their doors for the day with state authorities continuing to warn people to stay inside where possible.

"For those vulnerable groups over 65s, under 15s, pregnant women and people with existing lung/heart disease or diabetes, we are saying avoid exposure to the smoke by staying indoors and limiting physical activity," Victoria's Chief Health Officer Brett Sutton said.

Photo taken on Dec 20, 2019 shows a helicopter working at Lexton bush fire site in western Victoria, Australia. (WAYNE RIGGS / CFA / HANDOUT VIA XINHUA)

Photo taken on Nov 11, 2019 shows the bushfire in Taree in New South Wales, Australia. (BAI XUEFEI / XINHUA)

Photo taken on Nov 11, 2019 shows the bushfire in Taree in New South Wales, Australia. (BAI XUEFEI / XINHUA)