Aer Lingus is to impose further temporary pay cuts on staff, who will only receive 30% of their normal pay and hours from 21 June.
The airline had already reduced the pay and hours of staff to 50% of normal because of the collapse of aviation traffic and passenger numbers as a result of the Covid-19 crisis.
However, in a letter to staff this evening, the company says that their pay will be cut to 30% of normal from 21 June to 29 August, though the airline reserves the right to extend the cut beyond that date.
It is understood that the cuts will apply across the airline, in addition to staff lay-offs already announced at Shannon.
In the letter, seen by RTÉ News and entitled "Re: Notification of Temporary Reduction to your Hours of Employment and Pay", Aer Lingus notes that it is continuing to experience the significant impact of the pandemic "...and its ongoing detrimental impact on our flying schedule and our current business activity".
"We have concluded that we are unable to maintain your current hours of employment at this time and deem it necessary to temporarily place you on short time by reducing your normal working hours to 30% of your contractual hours from 21 June 2020 until 29 August 2020 inclusive," it states.
"These measures will be kept under review during this period and may be extended, revised or be subject to further change based on business need and work requirements which will be notified to you," the company adds.
In addition to basic pay, the cuts will also affect pension contributions, and other related employment benefits.
It is understood that management will be working 100% of hours for 50% of pay.
Some other roles will see people receiving half salary for half of normal hours, while most will see pay fall to 30%.
Aer Lingus is already availing of the Temporary Wage Subsidy Scheme.
The airline declined to comment on the notification to staff.
However, SIPTU aviation official Neil McGowan said it was extremely disappointing that Aer Lingus had decided to take "unilateral" action to further reduce the working hours of union members.
He said the union continued to insist that the current pay arrangements (50% plus top up) are continued beyond 21 June, and for the duration of the crisis.
He also called on management to engage immediately with unions.