The National Council of the Irish Hospital Consultants' Association (IHCA) has rejected the deal secured by accident emergency nurses.
Members of the INO and SIPTU decided to suspend their work-to-rule in A&E departments from 8 a.m. yesterday for five weeks to allow new arrangements on admission and discharge to be implemented.
However, following detailed discussions, IHCA officials this afternoon decided they had a number of concerns relating to the nurses deal that meant they could not endorse the deal.
"This agreement is one which will give high-speed medicine as opposed to high-quality medicine, therefore it is not one we can endorse," a spokesman said.
Nurses favour the creation of an agreed formula which would enable bed managers to cancel planned admissions where a certain number of emergency patients had been waiting for beds for more than a certain number of hours. But the consultants say only they have the right such decisions.
The "emergency response" formula would also allow bed managers to ask consultants to do extra ward rounds to see if there were any in-patients who could be sent home or to nursing homes.
The IHCA and the Irish Medical Organisation (IMO) have warned that any new arrangements must respect the contractual obligation of consultants to their patients.
The IMO have sought a meeting with health employers to express their concerns.