Australia's COVID-19 cases and death rates were the third highest in the world per capita during the past week, and the numbers are getting worse.

The latest figures show more than 12,625 Australians have died with COVID, and more than 5,000 are in hospital with the virus, including 159 in intensive care.

Professor Mike Toole, an epidemiologist from the Burnet Institute, said Australia was probably in the worst phase of the pandemic.

Professor Toole has studied the latest international data and found that Australia had some of the highest COVID-19-related numbers per capita.

"In the past seven days, Australia has ranked number three in cases per million population," Professor Toole said.

"That excludes the very tiny islands like the Channel Islands and other small places.

"We [also] ranked number three for deaths per capita, so much higher than the US, UK, France, Germany."

Experts plead with public to wear masks

Australia does mandate masks in high-risk settings such as aged care, hospitals and public transport but Professor Toole said it was not enough.

"If you look at other countries, a number of countries in Europe still have stronger mask mandates than Australia, and they have a lot higher compliance," he said.

Professor Toole pointed to a Burnet Institute study that showed mask-wearing doubled when Victoria first made it compulsory in 2020.

"The messaging out there is very very confusing," he said, arguing Australians were not getting clear signals on mask-wearing and other precautionary measures.

"The other thing they must do is get boosters. Two doses is not enough."

Chief Medical Officer Paul Kelly released a statement saying the advice was clear — people should wear masks in crowded indoor environments beyond their homes.

'Relentless' toll on health workers 

Health workers have felt the strain perhaps more than anyone.

As the pandemic stretches on, doctors and nurses are becoming burnt out by the ongoing burden on the health system.

Kylie Ward, the chief executive of the Australian College of Nursing, said she was very concerned about health workers.

"They've been giving now for years and it's been relentless and this is our third winter," she said.

"It's not only their physical health but their emotional health and mental health and wellbeing I'm concerned about.

She said healthcare workers deserved empathy.

"We don't have enough nurses, and those that we do have must be well over exhausted now," she said.

"So, please be patient, be kind, wear masks, wash hands and practice really good infection-control measures to minimise the spread of this infection."