The Labour party national conference has passed a motion calling on the Government to obtain certain guarantees around employment and other issues at Aer Lingus if it is to accept any future offer from IAG.
While it is now Labour party policy, this does not apply to Government policy.
The final emergency motion put to the conference was strengthened, saying there should be no outsourcing of jobs alongside guarantees on conditions.
Dublin North TD Brendan Ryan moved the motion, saying "we end to judge every single deal on its merits."
"We judged this deal, and we opposed it. There may be some deal in the future which meets all our concerns and copper-fastens our connectivity and the terms and conditions of worker's employment.
"We would need to judge such a deal on its merits, should it be made."
John Dowling a Labour member from Dublin-Rathdown said the party needs to be realistic, as other offers will be made by other groups.
"The current shark in the water is IAG, and if it is not possible to do a deal or fend off IAG, there will be other sharks to follow - which may not be much to your liking."
Rural Affairs Minister Ann Phelan gave her backing, commending the motion.
In the end, the vote was passed overwhelmingly, but the motion is not binding on the party in Government should another offer come from IAG.