TORONTO -- The chief of staff at Mackenzie Health in York Region has issued an urgent call to doctors to be on the ready to pitch in with additional duties in order to help avert a “total collapse” of the health care system due to COVID-19.

The call went out Monday in a memo obtained by CP24. It paints a bleak picture of the hospital’s ability to continue dealing with a third wave of the virus.

“As you are fully aware, the health care system is being stressed beyond any previous surges in dealing with this third wave,” Dr. Steven Jackson, vice president of medical planning and chief of staff at Mackenzie Health said in the memo. “Our intensive care units, emergency department and internal medicine wards are beyond capacity. Those who have met this challenge are to be truly commended for working above and beyond expectations.”

Jackson goes on to say that current modelling predicts that the hospital’s ability to care for patients in a traditional way will not be able to keep up with demand in the coming weeks.

He says the hospital is looking for “creative and novel” spaces to care for the expected load of critically ill patients, as well as "creative models " of physician care.

“Many physicians will be asked to help out even if this is an area with which they have little recent experience," Jackson said in the memo. He added that “this truly is a crisis in the system” and as such he is asking for any physicians from the hospital or the region who feel able to participate at the hospital to contact them.

“This is truly a desperate time for us all and we are now making very challenging decisions to avoid a total collapse," Jackson concluded.

In a statement to CP24 Tuesday, Mackenzie Health confirmed the memo and said the hospital system is facing an "unprecedented” challenge.

“Wave three has put an unprecedented strain on the health care system, including immense capacity and staffing challenges,” the hospital said in an email. “We continue to do everything we can to prepare for a continued surge in COVID-19 cases to protect our patients and community.”

Similar calls to arms have gone out to doctors in other hospital networks around the GTA in recent weeks, as health care officials try to figure out how to deal with the unprecedented strain caused by the third wave.

A memo to staff at the William Osler Health System last week said the hospital urgently requires additional help from doctors.

It said 100 physicians from across various departments were needed to help staff the ICUs as physician extenders. The memo called for doctors from surgery, anesthesia, pediatrics, emergency medicine and family medicine to help work 12-hour day and night shifts in the ICU.

York Region reported 519 new cases of COVID-19 on Tuesday and 564 on Monday, adding to a new total of 3,681 active cases in the region.

Data published by the region show that an average of 50 people a week have been hospitalized with COVID-19 in York Region over the past three weeks.

More than 18,000 people with COVID-19 have been hospitalized over the course of the pandemic in Ontario, with 3,305 of them ending up in the ICU.

Overall Ontario reported 3,670 new cases Tuesday.

A month-long stay at home order went into effect for Ontarians on Thursday as the province tries to quash runaway case growth made worse by the more highly contagious variants of concern, which now make up the bulk of cases.

- With files from CP24's Beatrice Vaisman