Workers who answer 999 calls claim their toilet breaks are being limited.
Staff say they were informed of a new toilet break policy, just hours after they announced their intention to ballot for industrial action.
They are demanding to be paid the living wage of €11.50 an hour.
The Communications Workers Union (CWU) - which represents the staff - says the new policy allows a maximum of seven minutes for a single toilet break.
And if the emergency call operator needs more time, they have to seek specific permission from line management.
They are allowed a total of 19 minutes of toilet breaks during a 12 hour shift.
CWU General-Secretary Steve Fitzpatrick said: "The CWU has come across some strange and bizarre policies at call centres over the years but this one takes the biscuit".
"It is a gross insult that BT Ireland/Conduit choose to impose oppressive policies on workers who already do a very tough and stressful job".
"Workers that play such a central role in directing first responders to save lives are entitled to respect and dignity at their workplace. This is an invasion of their privacy and displays a total disregard for the dignity of the individual".
"The emergency call workers are being treated as if they were a bunch of school children who need permission to use the toilet. These are hard-working people delivering a vital public service", he added.
