So far in 2019, there have been at least 135,952 cases Down Under, compared with an average of 17,349 in the previous five years.
Nearly 300 people are believed to have died in the outbreak this year, a big rise on the 125 for the whole of the 2018 flu season.
Doctors in Britain say the increase in Australia could be a sign of what is to come in the UK this winter.
They said more work needs to be done on vaccination uptake for healthcare workers and at-risk groups, such as patients with diabetes or asthma.
And they have called for an increase in the number of hospital beds.
Dr Nick Scriven, president of the Society for Acute Medicine, said the Australian figures “make grim reading and, if extrapolated to the UK, will cause major stress to an already overburdened system in terms of numbers if not severity”.
He added: “One concern is that last year we saw predominantly one strain of influenzas but already there are reports of two or three strains significantly circulating in the population that could complicate vaccination.”
The president of the Royal College of Emergency Medicine, Dr Taj Hassan, told the Health Service Journal (HSJ) that the Australian figures look “very scary indeed”.
He went on: “We struggled last year (in A&Es) in incredibly benevolent circumstances.
“I am not sure that is going to happen this year. It is very important that we prepare. Perhaps we need to start vaccination early and set aside some money.”
Saffron Cordery, deputy chief executive of NHS Providers, said: “The spike in flu we are seeing in Australia could be a worrying signal of what is to come for health and care services this winter.
“Trusts are already working hard to improve vaccination uptake among staff, and will strive to improve this further.
“We must get immunisation rates as high as possible. We must also get our resilience plans in place as early as we can.”
But Public Health England (PHE) claimed flu activity in Australia was not necessarily a sign of what will happen in the UK.
“We are monitoring closely, to see if the high levels of activity continue or if this early activity represents the peak for this season,” said Dr Richard Pebody, head of PHE’s flu surveillance.
Meanwhile, England’s A&E departments have recorded their worst June performance since current records began, with just 86.4% of patients seen within four hours.