The Irish Medical Organisation has criticised the Department of Health's "lack of consultation" over plans to allow some nurses the right to prescribe certain drugs independently of doctors.
Dr James Reilly, president-elect of the IMO, which represents more than 6,000 doctors, said many issues should be resolved before any nurses were given limited prescribing powers under pilot projects due to be announced next month.
"There has been no consultation with us over this. It has been mentioned in the media, but at no stage has there been an attempt to liaise with the profession to develop this," he told RTÉ's News at One programme.
The Minister for Health, Mr Martin, is expected to announce officially the launch of several pilot projects next month which would see up to 200 nurses involved in the prescribing of a list of drugs, such as adrenaline, paracetamol and insulin, in certain situations.
The Irish Nurses' Organisation (INO), however, said changes in prescribing practice were signalled as long ago as 1998 and that no one in the medical sector should feel threatened by the move.
The pilot projects will be carefully monitored and assessed, according to Department of Health sources, and the results will be used as part of plans to extend limited prescribing rights to fully-trained nurses.
However, Dr Reilly said the IMO and other professional bodies should have been involved in the establishment of pilot projects because of the issues at stake for all involved in the sector.
"Medico-legal issues are major at the moment, as are enterprise liability issues with consultants, and we have the ever-rising cost of medical insurance. How will this work with nurses prescribing?" he said.
"The last thing I want to give is the message that we're not in favour of this. I think this could be a useful initiative down the line, but I think an awful lot of matters need to be fleshed out in relation as to how it's going to work."
The INO's general secretary, Mr Liam Doran, said the pilot projects would be carried out in carefully defined and limited circumstances.
"This is aimed at improving healthcare for patients and allowing nurses, who are in hospitals and nursing homes on a 24/7 basis, to prescribe a set range of drugs," he said.
Mr Doran also insisted that the pilot projects, already delayed by six months, should not be held back any longer, despite doctors' concerns.
The Irish Pharmaceutical Union, meanwhile, which represents 1,500 pharmacists, called for the authority to prescribe certain medicines for routine ailments to be given to pharmacists also.