Image source, Image caption, Routine surgeries have been delayed due to the pandemic
The Minister of Health said she "could not rule out " the suspension of routine services during the winter months.
Eluned Morgan said pressure on staff could force some health boards "to consider how they are performing their services ".
NHS Wales boss Andrew Goodall said declared that the health service is facing its " hardest time as it tries to catch up with a backlog of scheduled treatments.
Measures also remain in place in hospitals to stop the spread of Covid.
"We are very keen to see health boards trying to do as much routine work as possible, but I can don't make any promises when we still don't know what we're going to face this winter ", Ms. Morgan told Hfrance.fr Wales Live program.
The first wave of the pandemic saw surgeries canceled to help free up beds, and although the third wave brought in fewer Covid patients, they add still under pressure.
On Wednesday, the daily average of patients with confirmed Covid was 439 - the highest figure this month so far, although well below the figures seen in previous waves .
Bed occupancy rate reached 90% this week, with the average number of patients treated for all conditions highest seen in acute care hospitals in Wales since the start of the pandemic.
The NHS in Wales is trying to tackle a backlog of waiting lists as hospitals face the challenge of treating patients with the disease of Covid.
Scientific modeling for the Welsh government suggests we are heading for a peak over the next few weeks in terms of the number of hospital cases of Covid, although a new report says "the exact turning point is not clear ".
Ms Morgan was also asked about restructuring vascular services at Betsi Cadwaladr's health board after a woman said her husband was at risk of losing both of his legs due to a flawed reorganization.
The Minister of Health said she would keep her feet on the board of health to get better results.
Media caption, Pete Calley: 'He was such a happy person ... but it 's gone '
Since 2019, the gens from North Wales have had to travel to access a central vascular service in Bodelwyddan.
Pete, 51, awaits surgery to amputate his second leg due to complications from diabetes with which he has lived for 22 years, his wife saying "I 've lost the man I married ".
"I have spoken to people who are very disappointed with the restructuring that has taken place in north wales and have spoken to rd health boa about the restructuring and we expect better results "said the health minister.
The Board of Health says it remains "committed to providing a stable and high quality vascular service for North Wales ".