The Otago Daily Times understands the town's general practitioners who work after hours - believed to number six - have told the Southern District Health Board they no longer wish to do so.
However, Dunstan Hospital general manager Karyn Penno said it should not be cause for concern, because there was always a doctor on duty at the hospital for serious cases, although the hospital did not have a walk-in emergency department.
A source, who wished to remain anonymous, said the reasons for the change were not money-related but "more about work practices".
The source said it was hard to attract locums and short-term staff because of the "unsociable" nature of on-call and after-hours work.
The ODT was also told after-hours care by a GP was meant to be for emergencies only, but if a problem was serious, a person could still go to the hospital, despite its lack of an emergency department.
Ms Penno said the area was serviced by an excellent St John team who were all "highly skilled", but if GPs withdrew their after-hours service in December, she did not know how patients with non-serious injuries would be treated.
"But I understand the concern ... St John are highly skilled and there are lots of options that are going to need to be worked through.
"It's too early to say what's going to happen. It is something we will all work together to resolve."
She said she had not discussed the issue with the district health board or the GPs yet but St John should always be the first point of call and if the problem was serious enough, a patient would be taken to the hospital.
"The hospital will continue to operate as normal."
Southern Primary Health Organisation chief executive Ian Macara said, when approached, he could not comment "at this stage".
GPs also declined to comment.
Southern District Health Board representatives could not respond before the ODT's print deadline.
"St John will consult and follow up on this," a St John spokeswoman said.
