Four residential homes in Londonderry, Strabane and Limavady will close if plans go ahead.
The trust is due to discuss the proposal at a board meeting on Thursday.
Around half of all care homes in Northern Ireland are set to close as part of the Transforming Your Care (TYC) programme, which was agreed by Health Minister Edwin Poots.
But last week it was revealed that all nine homes in the Northern Trust area could be closed under the scheme.
SDLP Foyle MLA Mark H Durkan spoke to families and staff at the William Street home in Derry following a meeting with the Trust officials on Wednesday evening.
"Staff are obviously very concerned about what the future might hold for them, whereas families of the residents in William St are confused, angry, they're very upset," he said.
"It seems to me and it seems to the staff, and more importantly to the residents that it is a done deal.
"There is talk of a consultation period for 12 weeks following tomorrow's board meeting, however it does seem to be a fait acommpli."
He said families are confused over where their elderly relatives will be cared for if the closures go ahead.
Mr Durkan added: "They are angry that these closures are being carried out as part of a cuts agenda yet are being peddled as an improvement in health care and they're afraid of the upheaval and the upset that this is going to cause."
Public service union NIPSA has claimed the Southern Trust was also considering similar closures.
Alison Millar, NIPSA Deputy General Secretary said: "While not unexpected given the announcements last week it is an absolute disgrace that the Western Trust and seeking to effectively evict 73 residents from their homes.
"NIPSA believes that irrespective of the outcome of any public consultation the Trust and the Health Minister have already decided and will try and force through closures of these residential homes and move these elderly residents mainly to the private sector.
"It is a disgrace that these vulnerable adults are being treated in this manner - they are seen as just a commodity that if it no longer suits the Trust Delivery Plan can effectively be gotten rid off."