The two nurses working at Tenterfield hospital without a doctor the morning a patient died there are "very distressed" and fear their calls for help have "fallen on deaf ears".
Ms McKeough said the union would continue lobbying the health minister and local health district on the issue of hospital staffing, which had residents "very heightened".
"[Union members] have been campaigning for quite some time about the staffing levels; they have been waving a red flag, as have the community, saying two [nurses] is not safe.
"Despite this, the local health district has refused at every turn to even consider providing support."
The man went into cardiac arrest while there was no doctor on shift or on call; nurses had to seek telehealth help from other hospitals and call paramedics to assist.
The nurses and paramedics unions say having a doctor present might not have prevented the death, but supporters say such incidents put nursing staff under "enormous pressure".
"The reality is: two people trying to manage a resuscitation is almost impossible," Ms McKeough said.
"They've also got to deal with the family and the phones ...
"All the health service needs to do is add another nurse - this is all over one nurse."
'Urgent inquiry' needed
The NSW Opposition has renewed its calls for an urgent independent inquiry into rural and regional health after the incident.
Health spokesman Ryan Park said: "Our health outcomes should not be determined by our postcode."
"It's simply unforgivable that there are hospitals with no full-time on-site doctors right across rural and regional NSW," he said.
Opposition rural health spokeswoman Kate Washington said people in these areas were "angry and scared" about their healthcare.
"Without doctors on site at hospitals, nurses are under too much pressure and patients are at risk," she said.
"Residents have a right to expect something that should be very simple: doctors at their hospitals."
State member for Lismore Janelle Saffin said it was "a tragic outcome" and offered her sympathies to the male patient's family and friends.
"I support the local staff at the hospital who provide the best care for our local community," she said.
"The community rightly expects, and deserves, to be able to see a doctor, whether it is the medical officer or a locum doctor, when admitted to their hospital's new Emergency Department," she said.