SIPTU balloted its members who are employees of Key Security last Thursday because the company, according to the union, has imposed changes to the workers' terms of employment without consulting with staff or SIPTU representatives.

The security firm, which employs 28 staff in Limerick, provide security services at the Mid-Western Regional Hospital, the Regional Maternity Hospital, St John's Hospital and Southill House.

Twelve of the security staff are union members.

A SIPTU spokesperson said difficulties with Keg Security have been ongoing. "We have experienced difficulties with this union for some time," Mary McElligott told the Limerick Leader.

Voting in favour of industrial action was not a decision that union members took lightly, she said, given the nature of employees' work ensuring the security of hospital staff.

The accident and emergency department at the Mid-Western Regional Hospital in Dooradoyle has been the scene of violent altercations, and aggressive people under the influence of alcohol, and in such circumstances a security service is vital.

"We did ballot members in March on this issue and to be fair to the employees, they gave the company an opportunity to rectify the discrepancies," Ms McElligott said.

The company did make changes at the time but "reverted back to their old ways" since.

According to the HSE the Mid-Western Regional Hospital is aware of internal disputes relating to Keg Security but it has not been involved in them. The hospital will be monitoring the situation to ensure that it is in a position to respond to any possible disruption.

Union members are expecting a response today from SIPTU whether or not to go ahead with strike action.