SIPTU members at Dublin Airport are threatening industrial action in a dispute over the payment of wages.
The union says the daa has repeatedly failed to pay staff on time and that there have been inaccurate payments to workers for the last nine consecutive months.
SIPTU worker representatives employed by the daa in Dublin Airport have declared no confidence in management and have begun preparations for balloting union members for industrial action.
"This week, wages for thousands of airport workers that were due to be paid on Wednesday 21 September did not arrive in their accounts on time," said SIPTU Division Organiser Karan O Loughlin.
"This debacle is the latest in a series of ongoing and consistent irregularities with the payment of wages to our members. These have included under payments, overpayments or no payment at all," she added.
The union is blaming a payment system, which was introduced by the daa in 2019.
The daa said in a statement that Wednesday's pay arrived in workers' accounts "a little later in the day than normal" and that as soon as it became aware there was an issue with the bank transfer, it informed all staff and apologised for any unnecessary stress or inconvenience the temporary delay may have caused.
The daa said the issue was completely separate to a payment problem that occurred due to a third-party provider being impacted by a cyber-attack in December 2021.
"Management has been in regular and frequent contact with all our trade union partners as we worked through the issues caused by that outage," the daa said in a statement.
"Daa has acknowledged the concerns with payroll that SIPTU has raised on behalf of its members and we call on them to withdraw the unnecessary threat of industrial action and to continue to engage with us to resolve the issues within our agreed dispute resolution procedures."
"This matter has been and remains a top priority for both the daa board of directors and executive team who are fully committed to resolving any outstanding issues," the company added.