Nurses at Bulli Hospital claim they have no guidelines for "rejecting seriously ill presentations" when the changes to the emergency department take effect.
"A major concern is the process around transferring seriously ill patients to Wollongong, who present at Bulli," said the NSW Nurses and Midwives Association.
"The nurses have no guidelines on how to reject a seriously ill presentation, especially when they already have difficulty getting Wollongong ED to accept transfers and the ambulances are often so busy they are reluctant to move patients who are in beds," union general secretary Brett Holmes said.
"You can't just unilaterally close something like an ED without having fully developed policies and procedures in place and ready to go, especially as the hospital approaches one of its busiest periods of the year," Mr Holmes said.
Under existing protocol, when a patient presents at Bulli Hospital and cannot be appropriately treated, he or she is stabilised and an ambulance is called.
The Illawarra Shoalhaven Local Health District's escalation plan will remain the same.
Health Minister Jillian Skinner said yesterday the emergency sign at Bulli had been removed prior to the busy holiday period so people knew exactly what services they could expect.
"Signs at Bulli Hospital, like all hospitals, should reflect the services provided at the facility for patients," Ms Skinner said.
"The Health Care Services Plan released last month underlined that the Bulli and Coledale Hospital precincts will be developed into centres of excellence for aged care. However, Bulli Hospital's role in the district's network of emergency services was also confirmed in the plan," she said.
"I understand ISLHD board chair Denis King has made clear that Bulli Hospital will have a defined role in the provision of emergency primary care services across the district.
"Professor King has repeatedly stated that there is no intention to close Bulli Hospital and it will continue to play an important role in providing health care."
Last week Professor King said work had begun on the transition to an Emergency Primary Health Care Centre at the hospital, so people understood Bulli specialised in "lower acuity" emergency presentations while more serious cases should be directed to Wollongong.
The 2008 Garling Report into Acute Care Services in NSW Public Hospitals found ED presentations at Bulli numbered 5864 in 2011-12.
"This total volume appears too low for sustainable medical staffing and diagnostic capability 24 hours a day, seven days a week," the report found.