The agreement, made in April 2020, will see up to 57,000 nurses and more than 100,000 staff made available to affected areas around the country.

"It's a workforce which is skilled, planned, appropriate and available," Health Minister Greg Hunt said on Tuesday.

"The states and territories will, where necessary, work directly with the staff and with the hospitals themselves ... it will be up to the states and territories to activate those."

Mr Hunt said taking this step was "planned, prepared and anticipated", and triggered by "any surge in either case numbers or hospital numbers".

The minister also activated the national medical stockpile to support states and territories with personal protective equipment shortages.

Chief Medical Officer Professor Paul Kelly said the healthcare sector had been preparing for workforce pressure for some time.

"This is the first time the health system has come under pressure to the extent that we're seeing in the last week or two," he said.

"I said on the weekend, and I stand by those statements, that we are either at or close to the peak of this in certain states."

Professor Kelly reiterated the Omicron variant is "a little bit less severe" than others.

"It's been seen in the rest of the world and we are making the same plans as many other parts of the world have done in response to hospital admissions," he said.

Australian Associated Press