There are signs that coronavirus cases in Wales are beginning to stabilise, Wales' Chief Medical Officer Dr Frank Atherton has said.
But Dr Atherton also said the news should be met with ''cautious optimism.''
He said: ''There are some encouraging signs that cases of coronavirus are beginning to stabilise in Wales.
''The situation remains very serious, and we are still dealing with the added factor of the new, highly-contagious strain of the virus.
''However, over the course of the last few days, we have seen a small fall in the overall levels of the virus in most parts of Wales.''
Covid-19 statistics in Wales:
2,870 covid-related patients in Welsh hospitals
The average age of people in critical care is 59
The NHS are currently operating at 152% of critical care capacity
15% of ambulance calls are for coronavirus.
Dr Atherton was joined by NHS Wales boss Dr Andrew Goodall at Wednesday's coronavirus briefing who said despite the ''tentative and encouraging signs'' there are still real concerns over the NHS ability to deliver services.
He said: ''There are now around 2,870 covid-related patients in Welsh hospitals - the highest on record. We have now exceeded double the peak we experienced during the first wave in April.
''At that level, the NHS will have to make some very difficult decisions about the balance of services it can provide.
''More than a third of hospital beds are occupied by covid-related patients. We would not normally start the very busy winter period with a third of our beds unavailable for normal NHS pressures. This is simply unprecedented.''
It comes as new figures show the majority of patients admitted to intensive care units in Welsh hospitals are from deprived backgrounds.
Extended vaccination hours could be introduced if there is a ''real demand'' but the Chief Medical Officer said staffing and supply levels need to be considered.
Dr Atherton said: ''It depends partly on supply and we also have to remember that the same people who are working hard to deliver vaccines are the people who are busy on other duties so we need to make sure we don't destabilise the NHS by increasing activity elsewhere.''