A health board is considering cutting non-urgent, planned surgery for a period after Christmas to save money.
Hywel Dda, which is in charge of hospitals in west and mid Wales, said emergency and urgent operations would take place as normal.
It said it wanted to boost support for emergency and outpatient work.
Health boards in Wales face a potential shortfall of nearly £50m, with only one predicted to break even by the end of the financial year in March.
Hywel Dda said it was common in the NHS for planned surgery to be limited over Christmas.
However, it said that the changes might continue for a short period into January.
Tony Chambers, the health board's director of planning, performance and delivery, said: "As is standard practice in the NHS, planned (elective) procedures will be limited over the Christmas period to ensure we can meet the demand for emergency services and reduce any cancellations.
"No patient will be put at risk and emergency and urgent operations will take place as normal.
"Generally, this will only be in effect during Christmas week, but we are considering the possibility of extending this period for a short time in a small number of specialities.
"This is primarily to increase support for emergency and outpatient work during this busy time."
Other health boards appear to be taking varying approaches over Christmas.
Betsi Cadwaladr, which covers north Wales, said it was scaling back as usual over Christmas but not planning to extend it, while Cardiff and Vale said it was planning to carry out more elective procedures over the festive period.
Hywel Dda is one of seven local health boards in Wales and has four hospitals - Prince Philip in Llanelli, Glangwili in Carmarthen, Withybush in Haverfordwest and Bronglais Hospital in Aberystwyth.
It faces a £4m deficit despite receiving £33m extra from the Welsh government.
Only one, Betsi Cadwaladr, is predicting it will break even despite health boards being legally obliged to do so at the end of every financial year.
Health Minister Lesley Griffiths has offered them an extra £103m, but told them not to expect any more.
The Welsh NHS Confederation said health boards were "working towards" breaking even, but the scale of the challenge should not be underestimated.