Players said it was "hard to breathe" and visibility was reduced during New South Wales' Sheffield Shield match with Queensland on Tuesday.

Smoke from the continuing fire crisis in Australia has caused chaos in Sydney, bringing dangerous air quality.

"It's not healthy," said O'Keefe.

"It's toxic. That was shocking."

The Australia international added: "I don't have kids, but if I did they'd be locked up inside, and if I was at home I wouldn't be training or playing.

"For someone like me who smokes 40 a day, it's now like smoking 80 cigarettes a day."

Sydney has endured air quality surpassing "hazardous" levels for weeks, as about 100 blazes continue to rage throughout New South Wales (NSW).

Last week, players at golf's Australian Open complained of stinging eyes as smoke affected the opening round.

The SCG is one of the most iconic cricket grounds in the world

The haze on Tuesday has been described as the thickest to cover the city during the crisis.

NSW Health urged young children and the elderly to stay indoors with windows shut and postpone outdoor activities, however play continued on the fourth day at the SCG with O'Keefe taking 3-28 as NSW beat Queensland by nine wickets.

Air Quality Index ratings were monitored throughout the day but readings were never high enough to stop play.

Queensland captain and Australia batsman Usman Khawaja, who made 54, said it was "hard to breathe" but was "not unplayable".

"If it got really bad, we probably would have come off," Khawaja said.

"I've never played in anything like that in Australia.

"It was bad but it wasn't unplayable. I wasn't going to use that as an excuse to come off and make a fuss about it, or say it's unsafe."

New South Wales won to continue their unbeaten start to the season after six games