A GP surgery which has two bases in County Down is set to close early in 2023 unless new doctors can be found to take it on.
Priory and Springhill Surgery operates out of two sites in Holywood and Bangor and provides GP services for 14,525 patients.
The services are set to stop from 1 February 2023.
The Department of Health said it was working to find GPs to take over the practice.
Alliance Party assembly member Connie Egan said a solution needed to be found immediately as there was "a lot of uncertainty and concern".
"Access to GP surgeries is a fundamental part of our national health service," she added.
Ms Egan said her party was seeking a meeting with the Department of Health and doctors' union the British Medical Association (BMA) to discuss the issue.
A spokesperson for the Department of Health said patients had been notified and the surgery remained open for those who require GP care.
'Shock and alarm'
Stephen Dunne, Democratic Unionist Party assembly member for North Down, said the news was a devastating blow.
"There's real shock and alarm at this news that's been breaking in the last number of days," Mr Dunne said.
"It has left great concern for many thousands of users, including elderly and vulnerable who really need that physical GP and available and accessible service"
The BBC spoke to a couple leaving the Priory surgery, who described the news as "surprising and disappointing".
"You have to ring at eight o'clock in the morning and try to speak to a doctor, if they think it's necessary you can then go in and see them.
"It's almost redundant anyway, it's a nightmare.
"Where do we go to the doctors? Do we all end up going to A&E? We've had to do it in the past because we couldn't get a doctors appointment."
Between 2014 and 2022 the number of GP surgeries in Northern Ireland fell from 350 to 319.
The BMA's Dr Tom Black described the situation as "worse than it's ever been in 30 or 40 years" and identified 22 surgeries "in crisis".
"We cannot find anyone to take on these contracts, no private company would take them on, they can't make the ends meet financially," he said.
"Young doctors see the commitment and risk."
Dr Black said workloads, hospital waiting lists, funding and staffing levels were also contributing factors.
"We've got a real problem with doctors being forced to retire early because the taxation on their pensions is exorbitant to the point that some doctors are having to take out second mortgages to pay these tax bills," he said.
"We could have avoided a lot of this if we had trained enough GPs over the last 10, 15 years, which we didn't do.
"The most important thing is that we don't destabilise other practices.
"There are 12 practices around [Priory and Springhill] that could be destabilised if they move... you get a domino effect with multiple practices collapsing in one area."
In May, residents in Carnlough in County Antrim raised concerns about a significant reduction to the community's GP service after the village's only clinic cut its hours to two half days a week.
The Western Trust had to step in to save the Dromore and Trillick practice in County Tyrone after a GP could not be found to replace Dr Declan Morgan following his resignation at the end of June.
The trust has taken on the contract for the practice, which has about 6,000 patients, until March 2023.