The admission comes after 24 clinical staff from Yass Hospital in the Southern Tablelands wrote a letter to the NSW government saying the community was at "risk of harm" and urgent action was needed, Nine Newspapers reported.

The letter alleged no registered nurse was available in the days leading up to Christmas, and the hospital was run by a fill-in doctor and enrolled nurse.

In the following days NSW Health brought in a paramedic, who then ran Yass Hospital with an enrolled nurse.

Susan Pearce, Secretary of NSW Health, told budget estimates on Thursday she was aware of staff concerns about conditions around Christmas time.

She said a significant number of registered nurses became COVID-19 close contacts during this period and could not work, and NSW Health had sourced an intensive care paramedic to work at the hospital before Christmas.

"I'm not saying what we did by any stretch of the imagination was perfect, but what we did do under very difficult circumstances was attempt to keep the hospital, particularly the emergency department (operating)," she said.

Ms Pearce was "personally involved" in the decisions over hospital staffing in her role as the state health emergency operations control centre operator for COVID-19, she said.

She said it was important to note Yass was an hour from Goulburn and 45 minutes drive from Canberra, and, "We could not leave that emergency department unattended with no staff".

The Southern NSW Local Health District is now working with the Nurses and Midwives Association to address the concerns of staff from Yass Hospital, Ms Pearce said.

NSW Health Minister Brad Hazzard said about 6100 NSW Health staff were furloughed or considered close contacts during the Omicron outbreak.

"We have had amazing staff who were able to go from one hospital to another and worked long hours," Mr Hazzard said.

Mr Hazzard said Yass had its own staffing challenges but attracting doctors to regional centres was a national issue in states, whatever their political persuasion.

The minister was also asked about the recent banking of ambulances outside Wollongong Hospital in February, where patients reported waiting up to four hours for beds.

"Practices in a particular (hospital's) emergency department may not be as streamlined, or as efficient as others, for a variety of reasons" Mr Hazzard told the hearing.

He said throughout the Omicron and Delta outbreaks, NSW hospitals had dealt with various issues and may have had a mix of patients, particularly COVID-19 patients, who health staff needed to triage outside.

Ms Pearce said Wollongong Hospital had recently been "extremely busy" after a number of aged care residents were unable to be discharged.

"That has caused some issues back into the wards, and we are well across those issues."

She said Wollongong was one of the state's best performing hospitals and recent issues were not indicative of the overall performance.

Australian Associated Press