Industrial action looks increasingly likely at Aer Lingus after the breakdown of talks aimed at addressing a €750m deficit in the pension scheme.

Talks at the Labour Relations Commission between the airline and unions broke down yesterday.

Aer Lingus refuses to go to the Labour Court, and last night SIPTU warned that industrial action was now the only avenue left.

At a meeting next Tuesday, Aer Lingus unions are expected to back industrial action.

While Aer Lingus pilots are members of IMPACT, they are not members of the Irish Aviation Superannuation Scheme - the pension scheme at the centre of the dispute.

They are thus not a party to the current pension dispute or to any potential industrial action arising from it.

Aer Lingus said that they had not received any notice of industrial action, and were not anticipating disruption at this time.

They said that they will update customers should the situation change.

Minister for Transport Leo Varadkar has said Aer Lingus, as a private company, has the power to make the decision.

"It would be unusual for the Labour Court to hear a case related to a pension fund. Aer Lingus is a PLC and it's up to management and the board to take a decision on these matters."

Ryanair has urged Aer Lingus to resist what it called union attempts to featherbed their pension schemes - and has offered to supply aircraft to its rival in the event of a strike.

Ryanair owns just under 30% of Aer Lingus and has been attempting to buy it outright.

In a letter to Aer Lingus chief executive Christoph Mueller, Ryanair urged the airline not to make further contributions to address the €750m deficit in its pension scheme.

Ryanair spokesperson Stephen McNamara said Ryanair would also provide as many short haul aircraft as required - at market rates - to prevent disruption to passengers, and to defend the funds of Aer Lingus shareholders.

He notes that the Aer Lingus pension scheme was topped up with €104m of shareholders funds when the airline was floated in 2006.

Ryanair says that at that time, both unions and employees agreed that from then on, pension contributions would be fixed.

It also notes that staff were given 15% of Aer Lingus at the time of the flotation.

It also points out that a further payment of €35m in 2010 to pay off bank debts of the Employee Share Ownership Trust.

It accused unions of industrial blackmail and of bullying the airline into making what it called further unjustified contributions to the pension scheme.

Ryanair has also urged the Dublin Airport Authority to resist what it called union demands to "featherbed" their pension schemes, when the Aviation Regulator would inevitably pass on any such cost increase to passengers in the form of higher airport charges.

Ryanair also called on ICTU General Secretary and Aer Lingus board member David Begg to condemn the threat of strike action, and to confirm that he supports the Aer Lingus position.