Update 6.40pm: In a statement this evening, BT Ireland said is commissioning an independent contact centre expert to review the work practices at the 999 call centre, and to make recommendations.
The company added: "In the event of further threats by the CWU on ballots involving industrial action, we can confirm we have contingency plans in place to maintain what is a critical service for public safety."
BT Ireland said every operator in Conduit Global who works on the Emergency Call Answering Service (999/112) received a 10% pay rise in November 2015, backdated to July 2014. The 10% was also applied to other additional allowances and bonuses. The company said when the rates are combined operators can earn on average more than the "living wage".
(Conduit Global is the organisation which is subcontracted to provide operators in three contact centres.)
The Emergency Call Answering Service handles on average more than 5,000 calls a day and aims to answer each call within 0.6 seconds. Calls to 999/112 are free to the public.
On the controversial 'toilet break' policy, Conduit Global said: "There is no ‘toilet break’ policy at our three centres. As we manage over 5,000 emergency calls each day, there is a policy to ensure that none of these vital calls go unanswered so we need to cover any off phone time to ensure we always have the right number of staff to serve the vital emergency service.
"This allows employees to have short, frequent breaks away from their visual display screen and stretch their legs as well."
The company added: "Conduit Global and its employees have held a number of engagement sessions this week and will hold additional employee engagement sessions in all three centres next week, so we may listen to our employees concerns and ideas.
"We are using this feedback to review our policies and understand what remedies should be put in place to improve and adapt the working environment…Our employees are their own best voice as representatives as opposed to a small number of union organisers."
Staff at the 999 call centre are to vote on industrial action over the company's stance on toilet breaks, and other issues.
The Communication Workers' Union (CWU) has delivered ballot papers to members, saying they had asked their employer Conduit Global several times for a meeting to discuss a range of issues.
Last week Conduit issued a new policy restricting toilet breaks to a total of 19 minutes in a 12-hour shift. Staff are required to report to management before and after the toilet breaks, the union says.
The CWU said that if staff exceed their toilet-break allowance, they face disciplinary action.
Staff have described the policy as insulting, and are considering industrial action.
CWU general secretary Steve Fitzpatrick said: "It is not acceptable to the CWU that staff working on a state-funded contract and providing a vital emergency service to the public have been left with no alternative to achieve basic dignity and respect at their workplace other than to ballot for industrial action.
"Conduit/BT need to realise that the treatment being meted out to their workers will no longer be tolerated."
Other issues the union says are at stake include: