The Forsa trade union has said it is premature for Aer Lingus to be planning to lay off staff and reduce hours from June 21.
The union, which represents cabin crew at the airline, said there is still a month left for negotiations and still time to come to a solution.
Aer Lingus is benefitting from the State's temporary wage subsidy scheme, which will cease at the end of June.
Niall Shanahan from Forsa said it is too early for the airline to be saying they are cutting jobs.
Mr Shanahan said: "It makes sense to sit down at the negotiating table and look at other options and a sensible problem-solving approach to the particular challenges faced by the airline.
"We think that by declaring its intention to act unilaterally to lay off staff and cut pay and hours next month is really ignoring the opportunity that's in front of us.
"To have more detailed discussion and see how we can address the very particular challenges faced, not alone by Aer Lingus, but by the entire aviation industry, conscious of the fact that Ireland's commercial connectivity relies a huge amount on its aviation industry.
"We have time still."
Aer Lingus has been buffeted by the coronavirus crisis which has devastated the aviation industry.
Yesterday, Forsa official Angela Kirk represents cabin crew and other grades and said the national carrier’s plans were premature.
“The effect of Covid-19 is not just an issue for Aer Lingus and its staff.
“It’s the most significant crisis for the entire Irish aviation industry in a generation, with the potential to adversely affect the commercial connectivity of the country.
“To act unilaterally now, and to abandon the efforts to negotiate a solution to the current crisis, and plan for a future recovery, is to squander the time remaining to negotiate real solutions.”
In a memo to members issued after the meeting, unions said the airline had confirmed its intention to extend current arrangements for pay, funded in part by the Government’s wage subsidy scheme, until June 21.
The current official subsidy scheme is due to end next month but the caretaker Government has said it will continue in a modified way beyond that.
Negotiations on the restructuring of Aer Lingus have been taking place between unions and management.
Workers’ representatives led by the Irish Congress of Trade Unions (ICTU) met the company on Friday afternoon.
Airlines have been grappling with a catastrophic decline in customer demand during the pandemic.
They face challenges around profitability while ensuring social distancing when more flights begin running.
In March, President Donald Trump suspended travel from Europe to the US.
Flights within Europe have also been severely restricted.
On Friday, the Government made the completion of a passenger locator form a statutory requirement but has not followed the UK in introducing a 14-day mandatory quarantine for travellers arriving in the country.
The industry has argued that will dissuade visitors.
Aer Lingus is part of Willie Walsh’s International Airlines Group (IAG).
IAG also owns British Airways and Spanish carrier Iberia.
BA’s owner has confirmed 12,000 job cuts at the UK flagship will still go ahead despite the British Government extending its furlough scheme until the end of October.