Leading employment lawyer Andrew Tobin said offenders could be prosecuted in the most serious incidents.

"In the worst case, that's really a version of a criminal fraud," he told Sky News on Monday.

He said employers could send employees for an independent medical examination to uncover the truth.

"If it was to be discovered that you were bunging it on, or bunging on an original illness for an extended period, you would in fact jeopardise your employment," Mr Tobin said.

"If you want a job to come back to with the same employer when all this disruption is over then I would think long and hard about trying to fake a sick leave scenario."

Some general practitioners are offering to email medical certificates after phone appointments in a bid to reduce the spread of coronavirus.

There's also warnings for bosses who insist employees continue to attend in person rather than work from home amid the spread of the virus.

Mr Tobin said employers had a high duty of care to maintain worker safety, both at the office and while commuting.

Employers are also legally responsible for safety of their employees working from home.

Mr Tobin said there was no legal definition of an "essential" worker.

"Clearly people involved in frontline medical service and many government services are just obviously essential workers in the current scenario," he said.

Australian Associated Press