Australia captain Pat Cummins received some welcome news Friday when he was allowed to leave Covid isolation in Adelaide and return home to Sydney on a single charter flight.

The world's number one Test bowler was ruled out of the second Ashes Test against England just hours before it started on Thursday for being in close contact with a positive Covid-19 case.

Under South Australia state's strict bio-security rules he was required to isolate for seven days but has now been permitted to head home, where he must remain until the Boxing Day Test in Melbourne.

"Under the plan approved by SA Health, he will self-drive from isolation and then, with the appropriate PPE (personal protective equipment) and hygiene controls, take a single charter flight," Cricket Australia said.

"He will continue to observe all isolation requirements in New South Wales."

Cummins was at an Adelaide restaurant on Wednesday evening when a person at the neighbouring table was identified as positive for coronavirus.

He isolated when he became aware of the situation and has since returned a negative Covid test.

Australian players are permitted to dine out in small groups under Covid rules in place for the Ashes in Adelaide, but should steer clear of densely populated places. 

Cricket Australia chief Nick Hockley insisted Thursday that Cummins had not breached any of their protocols and should be available for the third Test in Melbourne on December 26.

In his absence, Steve Smith is captaining the side for the first time since a ball-tampering scandal in 2018, which led to his axing.