The Minister for Health has defended plans to build prefabs on hospital sites saying temporary short-term measures are needed to break the vicious cycle of overcrowding.

Simon Harris said he has asked the HSE to look at hospital sites suitable for modular accommodation to improve the situation for patients and staff.

South Tipperary General Hospital (STGH) and Mayo General Hospital will be amongst the first hospitals to use prefabs to treat patients.

STGH is at the "advanced stages" of preparation for competition for the modular accommodation.

The Irish Nurses and Midwives Organisation and the Irish Patients Association have raised concerns about the plan saying there is not enough staff for the increased bed capacity.

Stephen McMahon, Director of the Irish Patients Association, said: "It's not like going down to the local supermarket and buying a bed and putting it there. You need the staff, the doctors, the nurses, the technicians and all of these other skillsets there."

INMO General Secretary Liam Doran said staffing levels in South Tipperary General Hospital and Mayo General Hospital are not sufficient to deal with the current bed capacity.

Mr Harris said that 1,000 more nurses need to be hired to be able to open these extra beds.

The HSE said any hospital group that wishes to avail of temporary accommodation can do so within the terms of the National Framework.