The Dublin Airport Authority has ruled out increasing the funding it is prepared to pay to resolve the row over the massive deficit in its pension scheme.

The DAA said that with limited profitability and net debt of over €600 million, it could not afford to undermine its financial stability and future growth potential in responding to what it called "unreasonable and unsustainable" union pension demands.

The company described a meeting with unions today as disappointing - and accused them of seeking funding to provide pension benefits which were not sustainable.

It said those demands exceeded the terms of last year's Labour Court recommendation aimed at resolving the row, which is set to trigger significant cuts in pension benefits for members of the Irish Aviation Superannuation Scheme (IASS).

The DAA said that at today's meeting, management had reaffirmed its conditional offer to invest more than €50m up-front in a new defined-contribution pension scheme once the existing scheme is closed.

It says that the €50m upfront lump sum plus an extra €50m in higher ongoing employer contributions to the new scheme was sufficient and generous.

The DAA says it had also offered to evaluate how the upfront sum might best be distributed among employee members to mitigate the impact of benefit cuts.

The company called on unions not to threaten the company, its customers and the travelling public with unnecessary disruption, adding that it was prepared to re-enter discussions to achieve a solution.

After the meeting, union sources said the DAA had failed to present any new proposals which could realistically lead to a solution.

A similar meeting will take place with management at Aer Lingus tomorrow.

SIPTU has already balloted for strike action, and is expected to serve strike notice early next week.