Campaigners worried about a loss of services from Llanelli's Prince Philip Hospital have been holding a protest outside a health board meeting.
They say services such as A&E and maternity have been moved to Carmarthen and are concerned more will follow.
Hugh Evans, a retired surgeon at Prince Philip, says people are having to travel for "simple procedures".
The local health board reviewing the services at its hospitals said there would be consultation on any changes.
Mr Evans, who is backing the campaigners, said there had been a progressive removal of services from Prince Philip.
He told BBC Radio Wales: "In the past we've seen eye surgery, trauma, maternity, paediatrics and dental surgery removed.
"More recently over the past two or three years emergency surgery has been lost together with vascular arterial surgery, gastrointestinal surgery and emergency endoscopy."
Hywel Dda Local Health Board, which covers Carmarthenshire, Pembrokeshire and Ceredigion, said there had been about 20 protesters at the meeting.
It issued a statement on Thursday saying "that no change is not an option" although people would be consulted before decisions taken.
"Because of the rumours circulating, misinformation and the leaking of draft documents which is undermining public confidence, the board has decided that it will add an additional stage to the clinical services review in Hywel Dda prior to formal consultation," said the statement.
"This will provide the opportunity for the public to form their opinions from an informed position and for the health board to be able to listen to their views."
The health board said it will organise an extensive programme of activities, events and information sharing across all three counties starting before Christmas.
It added that it was committed to the future of its four main hospitals - Prince Philip, Glangwili in Carmarthen, Withybush in Haverfordwest and Bronglais Hospital in Aberystwyth.
Welsh health minister Lesley Griffiths said earlier this month some services had to be centralised to improve care but said no general hospitals would be downgraded.
But Mr Evans said if services were to be centralised it should be in Llanelli which is the largest town in the three counties.
"Llanelli is an area of relative poverty. People do not always have their own transport," he added.
"Carmarthen is at least 20 miles away from a lot of people and people are having to travel 20 miles for simple procedures.
"We have not got anything in Llanelli at the moment - not even basic services. All the people want are the core services that any community of 100,000 should expect."