The Victorian government has refused to answer questions about hospital surge capacity or the number of healthcare workers and medical institutions coping with outbreaks of Covid-19, with hundreds of health staff now in precautionary quarantine due to potential exposure to the virus.

An email from the chief executive of Victoria’s largest public health service, Monash Health, said 77 staff across the service were in precautionary quarantine following three potential sources of exposure. Infections have been found in five employees. Monash Health services a quarter of the state.

“We must use this opportunity to reinforce processes, to make sure that we all understand them, and are doing what we need to do to stay safe,” the email said, urging staff to use protective gear properly and undertake frequent infection risk assessments.

Meanwhile, 14 staff from St Vincent’s hospital in Melbourne are recovering from the virus, an email sent from the chief executive to staff on Thursday said. The emergency and general medical departments of the hospital are undergoing deep cleaning following “potential exposures,” the email said.

All emergency staff have undergone testing. There are 10 inpatients with Covid-19 at the hospital. The email said “a small number of emergency department staff” had contracted the virus, so precautions were being taken. There had also been a potential exposure in the intensive care ward, the email said. Contact tracing is underway and several intensive care and general medical team staff are now in isolation.

As of Thursday, 70 staff associated with the Royal Melbourne Hospital were also in precautionary quarantine, with 12 positive staff and 48 inpatients with the virus. The ABC has confirmed Melbourne’s Northern Health has 142 staff in self-isolation.

On Thursday, the state’s health minister, Jenny Mikakos, told reporters: “We have created more ICU capacity, more beds in our hospital system, and we have undertaken extensive training of our staff.” She said all metropolitan public hospitals would operate at 50% of elective surgery capacity, while private hospitals would remain at 75% capacity to free up beds.

But doctors and nurses have raised concerns in recent weeks that increasing numbers of critical health workers needed to monitor patients in those beds are being forced off wards and into isolation after being exposed to, or infected with, Covid-19. On 10 July, the state government stopped reporting the daily breakdown of healthcare workers and health institutions affected by the virus, but still included details about outbreaks elsewhere including in public housing towers and at schools.

Guardian Australia revealed on Wednesday that six staff affiliated with Melbourne’s Royal Women’s hospital are among those confirmed to have Covid-19 as part of Victoria’s recent outbreak. The Age reported five healthcare workers from the Royal Children’s hospital, which treats some of Australia’s sickest children, now have the virus, and that seven other staff members who work in clinical and non-clinical roles are self-isolating. Other outbreaks announced in recent weeks have occurred among paramedics, staff from the Alfred hospital in Melbourne, staff linked to the Northern hospital in Epping, staff and patients at Brunswick Private hospital, and at the Joan Kirner Women’s and Children’s hospital. However, the state government has not provided updated figures associated with those clusters in almost one week.

Asked by Guardian Australia directly about the number of healthcare workers now infected and how many health institutions were involved, a spokeswoman for Mikakos did not respond. No direct response was given to a question about the current surge capacity in Victoria, that is, the ability of hospitals to rapidly mobilise staff to meet a sudden increased demand.

“While we are starting to see an increase in hospital presentations, Victorians can be assured our health system is ready and able to meet additional demand if necessary,” a government spokeswoman said. “We’ll continue to monitor the situation closely to ensure our hospitals and staff are supported.”

Mikakos would only say during a press conference on Thursday: “Our health services are very well prepared to respond to the increasing hospitalisations, but we hope that this additional capacity will never be needed.”

The minister did not provide numbers on how many healthcare worker cases had been acquired in the community or in the workplace. The government has only said “most” cases have been acquired in the community.

There have been calls for a national database reporting health worker infections in real time. The federal health minister, Greg Hunt,
said information regarding healthcare worker infections is already captured in the national notifiable diseases surveillance scheme. “The protection for healthcare workers is a priority for all governments,” a spokesman for Hunt said.

But professor of global biosecurity with the Kirby Institute, Raina MacIntyre, who led calls for a new register, said the current surveillance system was inconsistent and did not capture all cases. “We did an analysis basically trawling through every report including of health worker infections including looking at government websites as well as reported cases in the media and found some discrepancies, and we’ve had differing reports from states,” she said. An independent panel was needed to review each new case, she added.

Victoria reported a record 317 new Covid-19 cases on Thursday and two additional deaths. The chief health officer, Prof Brett Sutton, said there were now 160 separate outbreaks across the state.

“Of course it’s a concern to see healthcare workers exposed,” he said. “I know some of them have been exposed because they’ve been interacting with patients and maybe those patients were not identified with coronavirus very early on because of unusual symptoms, but also there’s staff-to-staff transmission that’s occurring. I made the point before that PPE [personal protective equipment] is available and it needs to be worn universally. But no one can let their guard down in terms of wearing a mask or where they’re trying to keep a distance, including with other healthcare staff.”

Prof Diana Egerton-Warburton, an emergency medicine physician with Monash Health in Melbourne, said she was concerned the pressures of working in emergency departments meant some health workers found it difficult to maintain personal protective equipment [PPE] and hygiene protocols for their entire shift. “There will be months, years, we will be living with the virus and we need to ensure clinicians are using PPE in a safe manner,” she said, agreeing that a national register of healthcare worker cases was needed.

A nurse from a major Melbourne hospital, who did not wish to be identified, told Guardian Australia that health workers were concerned about the lack of government transparency around infections occurring in healthcare.

“I am very worried about the situation and the management [of health worker cases],” she said. “I’m really concerned about the increasing staff infections and am not seeing them reported anywhere.”

Following increased pressure to release the data, Sutton indicated that further details about healthcare worker infections would be announced on Thursday afternoon. There are now 109 people in Victorian hospitals with the virus, 29 of which are in intensive care.