Doctors in Gold Cost, Western Australia, are bracing themselves for a severe flu that has the potential to kill young children within a day.
The fear comes after three Perth children, all aged under five, died from the fatal strain in the past 72 hours.
Staff at The Gold Coast Hospital admitted its Emergency Department had been bursting at the seems with 'traditional winter-bed demand' exacerbated by a colder-than-normal winter.
One local general practitioner told The Gold Coast Bulletin he had treated four patients suffering from pneumonia in a single morning this week.
The doctor said the number of serious flu-like diseases had skyrocketed in recent days.
The increase in hospitalisation for the flu played a role in the number of public and private hospitals going on bypass recently.
The Western Australian Department of Health last night urged parents to see a doctor if children were showing signs of respiratory illness.
The department's director of communicable disease control, Dr Paul Van Buynder, said the speed at which the three children fell ill was a grave concern.
"While we do not want to create unnecessary panic, it is important for parents to be aware that the disease can cause serious illness within 24 hours," he said.
A Gold Coast Hospital spokeswoman admitted winter was a difficult time for hospitals.
"It's is a busy time for hospitals Australia wide," she said.
"There are a range of processes in place for each public hospital to manage the seasonal increase in the number of patients."
The WA Health Department advised all parents of young children to see a doctor for the flu vaccination if they had not already done so.
"Parents whose children have cold- or flu-like symptoms, including a cough and a fever, should see their general practitioner," said Dr Van Buynder.
He said one of the children had been identified with having the influenza A virus, which is covered by this year's flu vaccine, and it was likely all three children had that strain of the virus.
The children became critically sick within a day.
"It's not about large numbers ... we had three children who got sick very quickly," he said.
Two of the children fell ill in Perth's Princess Margaret Hospital for Children and tests revealed they had developed a form of pneumonia.
"Samples taken from the two children who died in hospital suggested they had secondary bacterial pneumonia," he said.
"We'll be able to confirm that over the next few days."
The third child did not receive hospital treatment.
It is not known if there are more children suffering from the virus in Perth or if it had moved across to the eastern states.