New measures have been announced by the HSE that will mean an end to Monaghan General Hospital provide acute services.
Around 130 staff including medical and administration will now have to be redeployed around the north east.
Staff in Monaghan are being briefed this afternoon by management about the changes.
When the measures come into effect all patients requiring acute medical treatment will be brought to Cavan General Hospital.
Some of the beds in the medical ward in Monaghan will instead be used to provide rehabilitation and step-down facilities.
Monaghan will continue to provide day services and be used as an ambulance base.
The treatment room will be converted into a 12-hour, seven-day minor injuries unit.
However, all serious cases will have to be sent to Cavan or Our Lady of Lourdes in Drogheda.
The HSE says it will soon have a new Medical Assessment Unit in Cavan to assess patients while more ambulances and crews are being provided.
It was proposed to implement the changes at the end of November.
However, as measures such as the MAU or extra ambulances are not yet in place, it is not now likely to take place until Christmas or early in the New Year.
According to the General Manager of the Cavan/Monaghan Hospital Group, Dermot Monaghan around 130 staff will have to be redeployed.
'We will protect jobs as best we can,' he said, adding that the rights of permanent staff or temporary staff who have acquired rights under law will be protected.
There has been an angry reaction to the news that Monaghan Hospital will effectively close as a front line facility.
Dr Illona Duffy, a GP and hospital campaigner in the town, described the news as devastating.
She said that Cavan could not cope with the number of patients it was already receiving and to add another 3,000 annual acute admissions to it was simply untenable.
Today's move was something she said they had warned about for years but had been told by successive Government ministers that it would not happen and she accused the HSE of 'playing with people's lives'.
