Defending French Open champion Ash Barty has confirmed she won't be defending her singles crown at Roland Garros in 2020, with border closures and COVID-19 concerns cited as reasons for her withdrawal.

Her French Open win in 2019 was her maiden Grand Slam victory but a new winner is set to be crowned with the World No.1 to remain in Australia.

Barty said border closures have made it difficult for her to train with coach Craig Tyzzer with 'health risks' in France due to coronavirus also an issue, with France experiencing 31,000 deaths from the virus.

“It has been a difficult decision to make but unfortunately I will not be competing in Europe this year,” Barty said in a statement. “Last year's French Open was the most special tournament of my career so this is not a decision I have made lightly.

“There are two reasons for my decision. The first is the health risks that still exist with COVID. The second is my preparation, which has not been ideal without my coach being able to train with me due to the state border closures in Australia.

“I wish the players and the French Federation all the best for a successful tournament.

“I now look forward to a long pre-season and the summer in Australia. It has been a challenging year for everyone and although I am disappointed on a tennis front, the health and well-being of my family and my team will always be my priority.

“Thank you to my fans for your continued support, I can't wait to play for you again.”

Barty had also previously opted out of the US Open, which is currently taking place without fans in attendance. The French Open will kick off on September 21 and will have a reduced numbers of fans in the stands.

Tournament Director Guy Forget says all players participating at the French Open will be housed in two designated hotels to reduce COVID-19 risk, with players tested “upon their arrival and will receive their accreditation as soon as the first negative test is returned”.

A further test will take place 72 hours later and then every five days, depending on a player's progression through the tournament.

Roland Garros will host 11,500 fans a day, less than the orginal hope of 20,000. With current French laws limiting gatherings to 5,000, the complex will be divided in three seperate zones corresponding with the showcourts with no crossing between zones.

The  Philippe Chatrier and Suzanne Lenglen courts will host 5,000 spectators while Simonne Mathieu will be restricted to 1,500. No tickets will be sold for the outside courts.