Outbreak managers replaced the entire St Basil's Home for the Aged staff with an emergency workforce on July 22 last year, during Melbourne's second wave.

Within hours of the handover, inexperienced nursing staff were struggling to care for the mostly Greek-speaking residents, who had already missed meals and medicine.

Senior doctors warned the afternoon before the handover that replacing regular staff was a "shocking idea" and the plan would turn out to be "a disaster", an inquest into the coronavirus deaths of 45 residents and another five residents who likely died of neglect, has been told .

But as the Commonwealth scrambled to staff the home's surge workforce, there was never a deadline set for establishing whether adequate numbers were possible, or if an alternative plan should be enacted.

Counsel assisting Peter Rozen QC on Monday said inserting an inadequate surge workforce into a facility where they had no background posed a risk to the standard of care for residents.

He asked Nicholas Hartland, deputy secretary of the federal health department's aged care group, whether there should have been a deadline for pulling the plug on the surge workforce.

"I don't think decisions happen like that in a fast-moving environment," Dr Hartland responded.

He said as of July 21 - the day before the handover - a complete evacuation of the Fawkner facility was not considered an option and the Commonwealth never guaranteed forming an adequate surge workforce was possible.

"The whole system was under a severe amount of stress at the time," Dr Hartland said.

The inquest was previously told by the night of July 22, Victorian health authorities found 115 private hospital beds that could be used for COVID-positive patients and a further 499 for COVID-negative residents, and these could be staffed within 24 hours.

Emails sent on July 23 by commonwealth health department COVID liaison officer Kim Wilcox showed federal authorities were open to using private hospital beds.

"Good to go as a principle - but not necessarily for St Basil's ... unless we still think it is needed," Mr Wilcox wrote.

Within days of the handover, 40 of the 117 St Basil's residents were hospitalised anyway.

On July 24, the Commonwealth directed that 40 residents at the home be transferred, because the burden on emergency nursing staff was too great.

Counsel assisting has previously told the coroner that this decision and its execution also happened in a uncoordinated fashion, and key St Basil's staff were left out.

The hearing continues before Victorian State Coroner John Cain.

Australian Associated Press