The Australian had been training for the Sydney Tennis Classic, a key warm-up tournament, but was forced to withdraw two hours before his match with Fabio Fognini at the Ken Rosewall Arena.

Kyrgios remains hopeful that he can play in the first Grand Slam of the year, which begins in a week on January 17.

Under New South Wales' COVID-19 regulations, Kyrgios must self-isolate for seven days, beginning from the date of the test.

"Hey everyone, I just want to be open and transparent with everyone," Kyrgios wrote on Instagram.

"The reason I have had to pull out of Sydney is because I tested positive for COVID.

"I am feeling healthy at the moment with no symptoms.

"I wish everyone all the best and to stay safe where you can.

"If all goes well I will see you all at the Australian Open."

Kyrgios also missed last week’s Melbourne Summer Set as he battled asthma.

The 26-year-old is now trying to find accommodation in Sydney which has a tennis court and would allow him to isolate and also prepare for the major, before travelling to Melbourne where the Australian Open takes place.

Melbourne is across state lines in Victoria.

If the draw works in his favour, Kyrgios could emerge from self-isolation and be available to play a first-round match.

Despite falling to 114^th in the world, Kyrgios is still seen by many as a dark horse for the home Grand Slam and is a polarising but high-profile player.

His previous best at the Australian Open came in 2015 when Kyrgios reached the quarter-finals, losing to eventual finalist Sir Andy Murray of Britain in straight sets.

Kyrgios has not played competitive tennis since September.