More than half a million Australians could experience long COVID with 110,000 of them suffering "significant impacts", according to modelling.
Researchers from the University of Tasmania and Deakin University used three different models to estimate how many people may have long COVID symptoms in early December.
They have called on the federal government to increase data gathering and surveillance, while the nation's peak body for general practitioners wants extra support to care for patients.
Long COVID is characterised by long-term health issues including extreme fatigue, which usually arise three months from the onset, with symptoms lasting at least two months.
The World Health Organisation estimates 10-20 per cent of people with the virus will experience long COVID.
The study's models suggest at least 160,000 Australians will likely be experiencing long COVID symptoms in early December and, for more than 35,000 people, their symptoms will significantly limit their activities.
The estimates increased to more than 500,000 and more than 110,000 respectively when researchers made adjustments based on work by the Australian National University.
"It is likely that several tens of thousands of Australian adults will be unable to work in December due to long COVID," report lead author Professor Martin Hensher said.
"This will not only have a detrimental impact on the health and wellbeing of our country, but many flow-on effects to the economy."
Prof Hensher said Australia was an outlier among similar countries in not having instituted large-scale national surveys about long COVID.
The study made several recommendations, including for greater surveillance of long COVID via regular Australian Bureau of Statistics and Australian Institute of Health and Welfare surveys.
More than 10.5 million Australians have contracted COVID-19. In the week to November 9, new cases totalling 54,661 were reported nationwide.
Doctors last month told a federal parliamentary inquiry that long COVID clinics across the country were being inundated with requests and waitlists are increasing.
President of the Royal Australian College of General Practitioners, Professor Karen Price, wants greater education.
"One of the challenges we face is poor patient awareness of long COVID and lack of access to medical and allied health appointments, not to mention the possibility of substantial out-of-pocket fees in accessing multidisciplinary care," she said on Thursday.
"Patients are reporting problems navigating the health system to get proper long COVID assessment, diagnosis, and appropriate treatment and that must change.
"There are not enough specialist long COVID clinics, especially in rural and remote areas, and those clinics that are up and running can't meet demand."
Health Minister Mark Butler said the department of health was leading the development of a national approach to long COVID.
The federal government has invested $130 million in COVID-19 research through the Medical Research Future Fund.
"It is clear we need to develop a focused national response to the phenomenon of long COVID," he said.
"We do not yet have a clear picture on the prevalence of long COVID in Australia."