A trade union said it will meet Health Minister Edwin Poots to discuss the fate of 26 Northern Ireland care homes belonging to beleaguered operator Southern Cross.
Southern Cross, which is the UK's biggest operator in the sector, is to fold after financial problems caused by rising rents and falling occupancy.
An attempt to stave off its financial problems by cutting thousands of jobs and underpaying its landlords by 30% failed.
Eamonn Coy, regional officer of trade union GMB, said it was "very fearful" that some of the less profitable homes in its 752-strong UK estate would be closed.
Yesterday, landlord NHP announced it would take over 249 homes - though none of those are located in Northern Ireland.
Mr Coy said: "We are meeting Edwin Poots soon in order to see what contingency plans there are in place for residents in Southern Cross homes.
"It's terribly worrying. It's not a question of our scaremongering -it's as serious as it can be as there is a prospect homes across the UK may close."
Northern Ireland's Southern Cross homes are not included in a tranche of 45 to be taken over by landlord and care home company Four Seasons or another 40 which will be taken over by Bondcare.
Southern Cross homes in the province include Castle Lodge in Antrim, Greenhall Lodge in Londonderry and Longfield in Eglington.
Around 1,100 elderly people are cared for in the homes though some, such as Longfield, are for young people with disabilities.
Four Seasons is the dominant care home operator in Northern Ireland with 67 properties. Other groups include Macklin Group and Priory Group.
Last week, Mr Poots said he had been assured by Southern Cross that the company would continue to operate the homes while they transfer to new owners.
He added: "Any new operators brought in by landlords will have to register with, and be subject to inspection by the Regulation and Quality Improvement Authority.
"My priority is the welfare of residents in Southern Cross homes. The Health and Social Care Board and trusts have contingency plans in place to ensure the welfare of residents."
The board said there was "every prospect" that continuity of care could be maintained for residents.