Operators answering Ireland's 999 calls will have to ask for management permission to use the toilet under a new policy introduced at Conduit Global, which operates the emergency call service.
In 2009, the contract for the Emergency Call Answering Service (ECAS) was awarded to BT Ireland, who then outsourced it to Conduit Global.
The Communications Workers Union (CWU) is currently balloting for industrial action in a dispute over pay, conditions and collective bargaining rights.
However, the union says that within hours of the ballot being announced, Conduit/BT Ireland introduced a new "Toilet Break Policy" which aims to "micro-manage" how and when 999 call service operators go to the bathroom.
According to the policy, staff must report to management before and after taking a toilet break.
ECAS operates from three bases across Ireland - East Point in Dublin, Navan in Co Meath and Ballyshannon in Co Donegal - but only one operator will be permitted to take a toilet break at any one time across the country.
Every worker is also prohibited from using the toilet for an hour of each working day.
In addition, no toilet break can exceed seven minutes in duration, to a maximum of 19 minutes per 12-hour shift.
If a worker needs more time, they must seek specific permission from line management and breaches can give rise to what the union described as "severe disciplinary action".
The CWU has described the new policy as grotesque, disgusting and an act of retaliation by a management regime that refuses to respect employees.
It said the policy did not allow time for workers to compose themselves after particularly traumatic emergency calls.
CWU General Secretary Steve Fitzpatrick said he had come across some strange and bizarre policies at call centres over the years, but the new toilet-break policy took the biscuit.
He described it as an invasion of privacy and an oppressive culture which displayed a total disregard for the dignity of the individual.
The operators at the Emergency Call Answering Service are seeking a pay increase to the living wage of €11.50 per hour.
They want a review of the company's on-call policy and full collective bargaining rights for workers.
The CWU says the company has refused to meet the union to discuss the workers' issues.
The union says the staff in question have been ranked as one of the best emergency call-answering services in Europe, with an average speed for answering an emergency call of 0.6 seconds.
Management sources denied the CWU claim that the policy was introduced as an act of retribution for the workers' decision to ballot for industrial action.
They stressed that the new policy on toilet breaks had been disseminated to staff last Thursday - before the company was notified of the impending ballot for industrial action.
They noted that staff had received a 10% pay rise in November backdated to July 2014, which had brought their basic wage rate to €11 per hour.
A spokesperson for BT Ireland said they were disappointed the actions of a trade union could jeopardise the service one of their suppliers provides
The spokesperson said BT Ireland was taking all steps to ensure they maintain their commitments to this essential service.
Other management sources noted that every operator in Conduit working on the ECAS - including CWU members - received a 10% pay rise in November 2015, backdated to July 2014.
They noted that the 10% increase also applied at additional allowances and bonuses, including night and weekend allowances, linguist remuneration, and if they were lead operators.
They also noted that there is an additional 10% bonus when Conduit operators hit their quality targets.
They claimed when those rates were combined, the staff were earning more than the living wage of €11.50 an hour sought by the union.
They noted the ECAS is a critical service that must perform to very high standards to answer calls from the public in emergency situations.
Conduit Global have also issued a statement in the wake of the claims in which the company say they "would like to emphasize our strong commitment to our employees".
The company also noted that "in periods of industrial action, allegations can be made in which the facts are not always evident, or are done to target emotions.
"We are committed to a positive work environment and an open dialogue with our employees to meet their needs."