St John of God Healthcare is on a mass recruitment drive for 150 Irish nurses to fill a predicted shortage of nurses in WA within 18 months.
Group chief executive Michael Stanford said it would be a struggle to find nurses when new medical facilities, such as the children's hospital and Fiona Stanley, opened.
A fifth of its proposed Irish workforce has arrived to work at St John's Murdoch and Subiaco. The rest are due before it opens its Midland hospital in 18 months.
"We were not going to take the chance (of missing out on nurses), so we have made sure we have sufficient staff for what we need to do," he said.
The Australian Nursing Federation supported claims of a looming nurse shortage, but warned employers not to rely on foreign nurses as a quick fix.
State secretary Mark Olson said 100 to 300 graduate nurses were unemployed and many others were underemployed after having hours cut from rosters.
"I object to overseas nurses being seen as a first resort, rather than a last resort," he said. "It's short-sighted if employers are constantly looking to poor economies when they can pick up graduates in Australia."
Mr Olson said he did not know enough about St John's recruitment program to comment on whether it had exhausted local options.
Dr Stanford said the Irish drive was one of a number of measures to beat the looming shortage, which included an increase to its graduate recruitment program over the past three years.
Many of the 1200 positions it will fill at Midland Hospital will come from Swan District hospital, which will close when Midland opens.
He said the Irish nurses were being hired on permanent visas because St John did not believe 457 visas offered adequate security.
The Health Department said it did not keep a record of how many local nurses were seeking work. It said WA had low vacancy rates in nursing and midwifery.
"This is expected to change as the new health and hospital services open, providing many career opportunities for nurses and other allied health staff," the department said.