A man wearing a protective face mask amid the outbreak of the coronavirus disease (COVID-19) walks past a Nike brand store in central Kyiv, Ukraine December 10, 2020.

Australia is currently witnessing a surge in Covid cases, influenza infections, and other winter illnesses, with the number of patients rising from 4,000 to over 5,000 within a week, a report released by health experts has warned.

The rise in infections has led to a high volume of emergency admissions in hospitals. While younger age groups suffered from RSV and influenza, pertussis and pneumonia were "unseasonably high" among school-aged children, The Guardian reported.

Bendigo Health, the largest hospital in Victoria, declared "code yellow," an internal emergency when the hospital systems are unable to meet the demand of the rising number of patients. There has been an increase of Covid-19 infected cases and patients with respiratory illness in the wards. Beds are full and support staff trained in nursing have been called in to help in the ICU and emergency departments, ABC News reported.

The Victorian government said 361 Covid-19 cases were reported from hospitals across the state, which was 191 more than the same time last month.

Australian Medical Association vice-president Simon Judkins said hospitals declaring "code yellow" indicates an "unprepared health system."

"If this is not the sign of a health system that is really struggling and is unsafe, it shows the system is not working," he said.

According to a report by ACT Health, Covid-19 case rose to 242 from 159 in the previous week and 146 in the week before. Hospital admissions rose from 28 to 67, but no one has been admitted to intensive care or ventilated.

The national data shows 3,788 Covid-19 cases among residents and staff in the residential aged care homes, with 469 active Covid-19 active outbreaks, that is 76 more since May 23.

The ACT government has announced precautionary measures, including mask mandate and Covid-19 testing for hospital patients.

Health experts have said that currently the infection is due to FLiRT, the Omicron subvariant, which is less severe. However, experts warned people not to be complacent, as that might lead to the situation spiraling out of control if vaccination is delayed and risks are not managed.

South Australian (SA) hospitals too have reported an increasing number of Covid-19 infections. A SA Health report stated 237 staff have been removed from work and 193 patients are admitted with flu or Covid.

Adrian Esterman, the chair of biostatistics and epidemiology at the University of South Australia, said the country was "right in the middle of another big wave" of Covid-19 and the situation is similar to last year.

"And it's still going up, so that's a major concern, especially since many hospitals have stopped mandatory face masks for their staff," he said.