Hospitals are planning to cancel operations and convert theatres to intensive care units if needed to keep people alive in a Covid-19 outbreak.
There are 221 ventilators in the country - the machines that keep people breathing if they need help.
College of Intensive Care Medicine committee chair Andrew Stapleton said hospitals were tallying up how many operating theatres could be used to boost that number if needed.
"When elective operating stops, we suddenly have access to a large number of anaesthetic machines, which function as support machines or ventilators, plus the staff that would normally be using them."
If that happened it would be a scenario that was "way past business as usual" and like nothing that had ever been done before in New Zealand, Dr Stapleton said.
Steve Kirby, who chairs the College of Critical Care Nurses, said nurses were getting extra training and being asked to consider leave carefully so they could be available if needed.
Many had recent experience of large-scale intensive care situations after the Whakaari/White Island and mosque shooting tragedies.
"The feeling is that they're prepared for worst case scenarios now. These are very upsetting situations, but they feel ready to deal with whatever is going to come."
Dr Stapleton said it has been upsetting to see some of the media coverage from overseas that suggested elderly people would be turned away from intensive care units.
"I want to assure older New Zealanders the hospital system is there for them as much as it is for the younger community," he said.
Ventilating - which involves inserting a tube in to the windpipe - was not a move taken lightly and it could be both physically and psychologically hard on patients.
But it was a much more complex a decision than just age, he said.
Plans on how to triage, or prioritise, patients for a Covid-19 emergency were being updated, Dr Stapleton said.
He hoped the new strict travel and gathering restrictions meant there would not be an overwhelming surge of cases but hospitals had to be prepared.