The operators of a Melbourne nursing home ravaged by a COVID-19 outbreak will have to give evidence to an inquest despite their argument it would be a “dress rehearsal” for future prosecution.

Kon Kontis and Vicky Kos last week faced the Victorian Coroners Court and formally requested to be excused from testifying at the inquest into the fatal outbreak at St Basil’s Home for the Aged on the grounds they may incriminate themselves.

The pair were running St Basil’s in July 2020 when 45 residents died from the virus and another five died during the outbreak.

Their counsel, Ian Hill QC, said allowing them to take the stand would be a “dress rehearsal” for subsequent prosecution.

“It exposes them to derivative use of their evidence,” Mr Hill told the hearing.

Counsel assisting, Peter Rozen QC, said there was a “very great public interest” in the inquest examining all lines of inquiry. The lawyer for 61 relatives of residents who died, Shifa Shaikh, agreed.

After a week of consideration, state coroner John Cain has ruled he is satisfied it is in the interests of justice for both Ms Kos and Mr Kontis to be required to give evidence.

“The evidence before the court is that they played a ‘hands on’ role in the day-to-day management of the facility,” he wrote in his written ruling.

“In particular, they played important roles in preparing for a possible outbreak of COVID-19 at the facility and responding to such an outbreak once it commenced on 9 July 2020.

“They are therefore clearly in a position to give direct evidence about nearly all of the topics identified in the scope of this inquiry.”

St Basil’s had its first COVID case on July 9, 2020, and outbreak managers replaced the entire staff with an emergency workforce on July 22.

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 had warned the afternoon before that replacing regular staff was a “shocking idea” and the plan would turn out to be “a disaster”.