The Australian Medical Association says the declaration of a 'Code Yellow' at Perth's Sir Charles Gairdner Hospital on Monday shows WA's health system is not coping with increased demand during winter.
A code yellow means that a hospital has an internal issue that disrupts its service.
The North Metropolitan Health Service, which includes Sir Charles Gairdner Hospital, confirmed the code yellow was declared around 3.30pm due to a capacity issue and lasted around four hours.
A spokesman said an issue in the Emergency Department triggered the code yellow, with management juggling patients around to free up beds and discharging appropriate people so others could still be brought in.
It's supposed to be a rare event - but the AMA's Dr David Mountain said incidents like this are becoming increasingly common and highlight that WA's health system simply does not have enough capacity, especially in the colder months.
"Our population has grown hugely, and we wanted it to grow, we had the boom and thought it would last forever, and of course the population increased and we just never caught up, we never planned to keep up with population demand," Dr Mountain said.
"Fiona Stanley was supposed to have 1000 beds, it's got around 700, so across the board there's shortfall."
In June, WA Planning Minister Donna Faragher told state parliament "as at April 7, 2016, 223 Code Yellow emergencies have been issued in the Western Australian public health system since January 1, 2016."
Dr Mountain said the way to reduce code yellows - aside from funding more hospital beds - was to develop better management practises for frontline services that take into account the changing levels of demand seen in Perth across the year.
"Every year we get the same old excuses, it was a bad winter. It was a mild winter this year, though September was very cold. We know winter is cold, so we need to plan for it properly.
"We want a properly managed and planned system matched to the population, and that we plan for winter - we can do things like reduce elective surgeries in winter when we know there can be overloads and increase them in the summer."
The code yellow at Charlies comes as the state government and opposition trade blows over ambulance ramping in the WA health system - where ambulances park outside hospitals while they wait to get a bed for their patients.
Shadow Health Minister Roger Cook pointed to new Health Department figures he said show that September was the second highest month of ramping on record, with a 174 per cent increase compared to September 2015.
This was after August figures represented the highest on record.
"Perth hospitals are under enormous pressure and patients are waiting longer and longer for the care they need. The problem of ambulance ramping and patient delays at our hospitals is out of control," Mr Cook said.
"Not only is it occurring at record levels outside our hospitals, we are hearing reports of a new kind of ramping occurring inside emergency departments, with patients placed in hospital corridors waiting to be seen by staff."
WA's Health Minister John Day hit back, saying the state's health services had just been through what is traditionally the busiest time of the year, and that ramping figures are now reducing.
"WA still leads the nation in treating or discharging ED patients within four hours. Throughput from EDs was slowed by a peak of 170 aged patients occupying metropolitan hospital beds," he said.
"WA has the lowest ratio of community aged care beds in the nation – the Health Department and the Minister are currently working with the Commonwealth to secure 75 community beds ASAP.
"There have been no cuts to hospital funding, overall health funding is up 5 per cent, and at Fiona Stanley Hospital, which is under ramping pressure, the budget has increased 6 per cent this year.
"All health boards are committed to reducing ambulance ramping."