Australians in the state of Victoria could face fines if they return to their workplaces from June 1 under the new COVID-19 rules announced on Friday.

State Premier Daniel Andrews explained that the working from home advisory had been upgraded, meaning that both employee and employer could be fined for breaching the rules, reports Xinhua news agency.

"If you're currently working from home -- you must keep working from home," Andrews said.

"For employees, that means an obligation to keep working from home. And for employers, an obligation to support them in doing so."

Several industries will be exempt from the order which involve essential employees who are unable to work from home, including supermarkets, public transport and frontline services.

The new order will remain in place for the foreseeable future as the COVID-19 challenge facing Victoria is far from over, Andrews warned.

"We're also being upfront: we don't yet have a timeline on when this might change, or how we might be able to get back to work as normal," he said.

The new order came after seven new COVID-19 cases were uncovered in the state overnight, including a student who tested positive after attending classes at a school in the northwest of state capital, Melbourne.

A teacher at the school had also previously tested positive for COVID-19, but the two cases were not believed to be connected.

The state's Chief Health Officer Brett Sutton said the two cases might suggest low levels of community transmission in the area and urged all people nearby with symptoms to get tested.