The world No.29 from Ukraine sparked controversy when she was filmed on a Tennis Australia charter flight to Melbourne for the Australian Open starting on February 8 despite testing positive to a banned substance in an out-of-competition sample.

She was then placed in a hard 14-day lockdown after a passenger on that flight returned a positive test of their own.

Her situation worsened when the International Tennis Federation released a statement on Sunday saying that an independent tribunal had denied 20-year-old Yastremska's application to have her provisional ban lifted.

It's left the Ukrainian locked in a Melbourne hotel with seemingly no remaining chance of competing at the Australian Open - and many questioning how she came to be on the TA-funded flight.

"Yastremska should never have been allowed to travel," Richard Ings, a former tennis umpire and ex-CEO of the Australian Sports Anti-Doping Authority, tweeted.

"She could have had an expedited hearing on her provisional suspension completed before she boarded the plane.

"The ITF/Tennis Anti-Doping Program is who should compensate Tennis Australia. They allowed her to travel."

The independent panel's decision is subject to appeal to the Court of Arbitration for Sport by Yastremska, WADA and the Ukraine anti-doping agency.

The rising star provided her sample in November and a WADA lab in Montreal found the presence of mesterolone metabolite, an anabolic agent on its prohibited list.

She has denied having used performance-enhancing drugs, says she believes the positive test was the result of a "contamination event" and has vowed to clear her name.

"I'm astonished and under shock, particularly given that two weeks prior to this test ... I tested negative at the WTA event in Linz," she said in a statement earlier this month.

"Only a very low concentration of mesterolone metabolite was detected in my urine. Given that low concentration and given my negative test two weeks earlier, I have received scientific advice that the result is consistent with some form of contamination event."

Meanwhile Portugal's Joao Sousa will miss his first grand slam since 2013 after a positive test to the virus delayed his departure.

He has since returned a negative test and has no symptoms, but with a 14-day quarantine on arrival has run out of time and will join Andy Murray as the second men's withdrawal due to the virus.

His withdrawal comes after it was revealed three non-playing people in hard lockdown who tested positive after travelling for the Open had the highly-contagious UK strain of the virus.

Australian Associated Press