A senior Welsh nurse has said that staffing is "the main problem" currently faced by the NHS with hundreds of healthcare workers off sick or isolating.
At one Welsh health board, Betsi Cadwaladr, more than 500 staff have tested positive for coronavirus in the last seven days alone.
The board is having to cope with this on top of the number of people off sick with other illnesses. They are relying on staff taking on extra shifts or overtime and using temporary workers to plug the gap.
It comes as health officials confirm Omicron is the most dominant strain of coronavirus in Wales with the variant accounting for 80% of cases in some areas of the country.
Read more: When is the next Covid rules review in Wales?
Mandy Jones, the deputy director of nursing at Betsi Cadwaladr, said maintaining good staffing levels is crucial for them to continue safely running emergency and urgent care.
She told ITV News Wales : "A major contributor for us being able to sustain services for emergency care is the staffing that we've got. So for example, this month compared to October-November, we've got double the amount of staff off.
"In the last seven days there's been over 500 staff who've tested positive for Covid...In addition to that, we've got other sicknesses and since March there's been about a 20% increase in the number of staff who are off as a total."
When asked if there was a danger hospitals could be overwhelmed, Ms Jones said she could not say. She explained they have managed to maintain all the services they possibly can but "it is a big, big challenge".
"We try and be as safe as we can, to provide the services that we need to for emergencies and urgent care," she said.
"The consequence of that is that we constantly have to risk assess continuously, hour by hour, day by day, as to what services we can provide.
"We have to rely on staff doing additional shifts, overtime and also the use of temporary staffing workforce, which we're very very grateful of but we would not be able to maintain emergency and urgent services without our phenomenal staff.
"It is a challenge, and a lot of staff including myself and my team included are tired. People are tired.
"But we are here to do a job, we try and do it well and we try and be as safe as we possibly can because we are responding to a pandemic that nobody thought would sustain the longevity it has."
Figures released by Public Health Wales on Wednesday show that the total number of positive coronavirus cases in Wales since the start of the pandemic has passed 600,000.
The latest data from Public Health Wales, covering the 24-hour period up to 9am on December 27, showed 5,929 new cases, bringing the total in Wales since the pandemic began to 600,682.
The total number of deaths within 28 days of a positive Covid test has now risen to 6,653 in Wales with a further two fatalities since the last data was released. The figures relating to deaths covers the 48-hour period up to 9am on December 28.
The latest seven-day infection rate across Wales, based on the seven days up to December 24, has risen to 1,079.3 cases per 100,000 population – the highest figure at any stage of the pandemic.
The local authority with the highest infection rate in Wales for the seven days from December 18 to 24 is Cardiff, where the figure is 1,339.8.
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