Managers at the country's largest residential care home for dementia patients say they have no option but to shut the centre.
St John of God's says health service funding for 60 in-patient beds at St Joseph's in Shankill, Dublin is far too low.
The centre is heavily oversubscribed, with 350 people on a waiting list.
John of God's chief executive, Emma Balmaine says the charity can't afford another large deficit in the New Year.
Labour Senator Kevin Humphreys says the government has reneged on its promise to keep the centre open.
He's calling on Health Minister Simon Harris to step in and increase the funding rate.