All nine residential care homes operated by the Northern Health Trust are set to close within five years, union bosses have claimed.
Health workers' union Unison said staff had been informed of the proposals in meetings over the last two days.
Health chiefs across Northern Ireland aim to close half of all state-run residential care facilities over the next five years as plans develop to put more focus on caring for people in their own family homes. The move is a key plank of health minister Edwin Poots' Transforming Your Care (TYC) reform agenda.
State-run residential homes account for around a quarter of the sector in Northern Ireland and privately-owned facilities will not be directly impacted by Mr Poots' plan. But Unison said closing all of the Northern Trust's care homes would be an "extraordinary move".
It claimed two homes - Pinewood in Ballymena and Westlands in Cookstown - were earmarked for closure in November, followed by Rathmoyle in Moyle in January next year. It said the remaining seven homes would close sometime between 2014 and 2018.
In response, the Northern Trust said its board members would approve a paper on the future of residential care at a meeting on Thursday.
A spokeswoman did not provide details about the number of potential closures, but said the proposals, which would be subject to public consultation, were based on the TYC objective of reducing the number of residential care homes and placing more emphasis on caring for older people in their own family homes.
Unison regional organiser Joe McCusker said: "The proposal to close residential care homes leaves no NHS provision for residential care in the Northern Health Trust area. This will remove any choice for vulnerable people to be cared for in an NHS care home.
"The Northern Health Trust needs to explain why they have taken the decision to close all its residential care homes."
A spokeswoman for the Northern Trust said: "The proposals contained in the paper are based on the outcomes of the regional consultation on Transforming Your Care which recommends that home should be the hub of care; that older people should be supported to remain at home and in their local communities; and that there should be a reduction in statutory residential homes for older people. The Trust cannot comment further until the Trust Board meeting has taken place."