A hospital is “stuffed full”, with more patients in beds with coronavirus than without, a consultant has warned.
Outpatient appointments and non-urgent planned surgery have been halted at hospitals in the Aneurin Bevan health board area.
Dr Ami Jones, an intensive care consultant at Grange Hospital, Cwmbran, said people were queuing in ambulances as there was “no space”.
Wales’ Health Minister Vaughan Gething said it was “incredibly serious”.
Mr Gething said another, un-named, major health board in Wales would also be withdrawing a range of non-urgent services shortly due to increasing pressures.
Wales’ First Minister Mark Drakeford warned the Welsh NHS was in danger of becoming the “national coronavirus service” when the number of positive Covid-19 tests passed 100,000 in Wales on Saturday.
Dr Jones, ICU consultant at the new Grange Hospital, said the hospital was “stuffed full with patients with very significant needs”.
She said keeping patients without coronavirus from getting the virus was hard and non-urgent treatment had to be halted.
She told BBC Radio Wales Breakfast: “As the numbers of patients with Covid in the hospital get more and more, that becomes more difficult. It’s not just pure beds, it’s trying to keep those patients safe.
“We have reached a tipping point, we have more patients that have Covid than don’t have Covid now.
“My ICU is probably two-thirds, three-quarters Covid patients who are not getting the care.”
On Sunday the health board apologised after a 73-year-old man waited more than 19 hours in an ambulance outside the hospital.
Ted Edwards’ family said he had been waiting outside following suspected sepsis or a stroke.
Dr Jones said people were queuing outside the hospital as there simply was no room inside, adding: “We are stuffed.”
“It’s very difficult, but the staff are working really, really hard, we are really sorry to the patients who are not getting the care,” she said.
Dr Jones said many staff in the hospital were now off sick, either due to stress, having to isolate after catching Covid themselves or having been in contact with someone who tested positive.
“We’ve had nine months of slogging it out,” she said.
“I’m not absolutely bursting to the gills in ITU, but I don’t have enough staff to look after my patients, I think that’s similar everywhere in Wales.
“We’ve got enough beds, and we’ve got enough ventilators, but that doesn’t make an ITU bed, we need nurses.”
She added: “It’s very tough, we don’t want to get to the point where we can’t deliver the care we want to deliver.”
On Saturday the health board said the number of positive cases in its areas were “increasing at an alarming rate” and so all non-urgent care was being halted.
Weekly infection rates across the five south-east Wales counties the health board covers averaged about 550 cases for every 100,000 people.
Speaking to BBC Radio Wales on Monday, Mr Gething said the situation was “incredibly serious” and he wished people would think about the impact on the NHS and on hospital staff when breaking Covid rules.
“I just don’t see how it can be much more serious before people recognise that the behaviour within our whole country… has a very real impact on the harm that is caused, and the way our NHS can keep us safe,” he said.
But Mr Gething said it was right to still allow people to have a period to meet others and travel during Christmas, as otherwise “people would make their own rules up”.