Hywel Dda Health Board has denied health union claims that it is cancelling operations this winter to save money.
But it says some surgery - such as knee and hip replacements - will be postponed.
The health board says it has a responsibility to ensure continued safe care at this time of increased pressure and is putting plans in place now to respond to the anticipated increase in activity over the winter.
Dr Phil Kloer, Director of Clinical Services, said, “There have been too many operations cancelled at the last minute due to emergency admissions. In previous winters, we had up to 160 additional beds in place often being managed by temporary staff. This is not a position we can sustain this year.
”We would like to reassure patients that if they have an urgent clinical need they will be seen. Emergency and cancer procedures, the vast majority of orthopaedic day surgery and other elective procedures will also continue.”
The health service union, UNISON, claims all planned orthopaedic surgery for four main hospitals in the Hywel Dda Health Board area have been cancelled until April 2014.
It says the hospitals affected will be Prince Philip, Glangwili, Bronglais and Withybush Hospitals.
Unison says the health board has to make financial savings and as a result hip and knee replacements will be cancelled.
UNISON Branch Chairperson, Wendy Evans, said, “The Health Board already has a waiting time of 15 months for patients awaiting orthopaedic surgery. This will clearly add at least another five to six months to their waiting time, causing further distress."
The union says it has written to the Health Minister, Mr Mark Drakeford to complain about the decision.