"I'd probably say at the moment I'm 50-50," she told ABC Radio, adding, "I'd gone as high as 97% but I've gone back to 50-50. We'll wait and see. The Western Australia state government would need to relax some restrictions for the Test to go ahead in Perth."
Matthews said earlier this month she was "very positive" about the match going ahead in Perth despite concerns that players and staff might have to quarantine upon arrival. She had also said Tasmania's attempt to move the Test to Hobart was doomed to fail.
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Matthews was far from certain on Saturday.
"It's a matter of whether cricket can meet those demands or not," Matthews added.
"One of the difficulties for cricket is just the high level of technology that's needed around the broadcast and the number of people that are needed around the broadcast compared to an AFL broadcast. It's one thing getting the players in (but) it's another thing getting the people who have to broadcast," Matthews said.
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The five-Test Ashes is due to begin on December 8 in Brisbane. Australia retained the Ashes when the teams last met in 2019 in England after a 2-2 series draw.