England's cricket team were cleared to play the second day of the third Ashes Test in Melbourne on Monday after two members of support staff and two of their family members were forced to isolate after testing positive for COVID-19.

A team spokesman initially reported only one positive test among a "family group" but host board Cricket Australia confirmed there had been several cases in the camp.

"Cricket Australia has been informed that two members of the England cricket team's support staff and two of their family members have returned a positive COVID-19 Rapid Antigen Test," CA said in a statement.

"The affected individuals are currently isolating.

"The entire playing group and all other support staff have undertaken Rapid Antigen Tests this morning and all have tested negative."

Cricket Australia boss Nick Hockley said England's players would all have the more thorough PCR tests after the close of play on Monday.

Hockley also rejected the idea of making changes to the remaining Ashes schedule. The fourth Test starts on January 5 in Sydney, where COVID cases have spiked in recent weeks.

"We've got great confidence in the protocols," he told reporters at the MCG.

"This is something that we're all having to live with."

The scare delayed the start of day two by half an hour but play went on in front of fans at the MCG without further disruption.

Australia lead the series 2-0 and can retain the Ashes with a draw in Melbourne.

Cricket Australia said there was no impact on other parts of the MCG but host broadcaster Seven Network confirmed one of its staff members working on the Ashes at the stadium had tested positive late on Sunday.

Australia captain Pat Cummins was forced to miss the second Test in Adelaide and isolate for a week after being identified as a close contact of a case.

Australian authorities are battling a surge in COVID-19 cases driven by the Omicron variant