Canberra, May 14 (IANS): Health authorities were investigating a COVID-19 cluster linked to a McDonald's restaurant in Australia's Victoria state, as the infections resulting from it increased to eight on Thursday.

So far half of the confirmed cases were employees of the restaurant and the other half household contacts of the workers, reports Xinhua news agency.

However, the origin of the cluster was unknown.

McDonald's Australia CEO Andrew Gregory told local radio station 3AW that most of the restaurant's roughly 100 employees had been tested.

"The vast majority of those have come back as negative. (But) it is possible we get a small number of positive infections," he said.

"The health department are investigating. We are taking it incredibly seriously."

Employees from a nearby McDonald's outlet were brought in, allowing the affected restaurant to reopen for business on Wednesday.

Meanwhile, a much larger cluster at a Victorian meat processing facility rose to 90 confirmed cases, with three new employees testing positive for the virus.

Also speaking with 3AW, Victoria's Chief Health Officer Brett Sutton conceded that the outbreak could have been better handled, and said that he would act differently with similar circumstances in the future.

"I think the very first linked cases that suggest transmission has occurred at the workplace, I think that could be a prompt to shut it all down," Sutton said.

"I think they're big calls when some of them will have 1,000-plus employees, but you need to reflect on what's happened here and what has happened overseas."

Widespread testing within Victoria also revealed nine cases of unknown origin, taking the state's total number of infections to 1,523.

As of Thursday, the total number of COVID-19 cases in Australia stood at 6,989, with 98 deaths.