Lingard Private Hospital has laid off 25 staff this week as part of what unions say is a statewide operational review by owner Healthe Care.
NSW Nurses and Midwives Association general secretary Shaye Candish described the situation as a "distressing and uncertain time" for staff, though it is unclear how many nurses are affected.
Healthe Care told the Newcastle Herald on Thursday that it was "reviewing the support service roles at Lingard Private".
"This has resulted in some changes to management and support roles across the hospital," a company spokesperson said.
The Health Services Union said it had entered into a dispute resolution process with Healthe Care over the Merewether hospital's job cuts and called on the company to "behave with a little decency".
The union's NSW secretary, Gerard Hayes, described the hospital's approach as "utterly callous".
"They've treated workers like an inconvenient line item rather than human beings whose lives and livelihoods have just been completely rocked," he said.
"The best thing would be for Lingard to sit down with the workforce, properly explain its plans and behave with a little decency.
"We need to preserve as many of these 25 jobs as possible."
Healthe Care also operates Maitland Private at Ashtonfield and 14 other hospitals across NSW, Victoria and Tasmania.
The company closed its Tuggerah Lakes Private Hospital on the Central Coast in October just five years after it opened.
Healthe Care executive chairman Geoff Sam said at the time that rising costs were putting pressure on some of Healthe Care's regional hospitals while others "have been established much longer [and] are breaking even and have a strong base of doctors".
The company said on Thursday that Lingard would "continue to recruit for frontline nursing and clinical staff to ensure the ongoing provision of safe, high-quality care for our patients".
Ms Candish said the nurses' union had been "made aware of a workforce and operational review across all NSW Healthe Care hospitals, including Lingard Private Hospital".
"At this stage, it is unclear how many nursing positions will be affected and the impact this will have on staff and patient care," she said.
"It is a distressing and uncertain time for our private health sector members, and we will be providing them with support throughout this process.
"We will be engaging in discussions with Healthe Care management to ensure our members are thoroughly consulted during the review."
The job cuts come seven months after Lingard lodged plans with the state government for an $80 million expansion which would almost double the hospital's bed capacity to 210.
The plans include a new two-storey building facing Hopkins Street and substantial changes to Lingard's existing buildings on either side of Merewether Street.
