At least five days of strikes are planned by unions at loss-making Iberia from as early as February 18 after talks over a cost-cutting restructuring broke down.

Parent company International Airlines Group is to press ahead with plans to trim capacity by 15% this year and will look at deeper cuts following the rejection of 3,147 job losses. The group had originally planned 4,500 job cuts.

A refusal to agree terms by last Friday’s deadline will mean deeper reductions than first envisaged, the London-based carrier has said previously.

IAG said it will move forward on “alternative” plans to return Iberia to break-even, in terms of operating cash flow, by the second half of this year and restore Iberia to an acceptable level of profitability by 2015.

Chief executive Willie Walsh said: “We’re disappointed that no agreement has been reached. Iberia is ready and willing to negotiate with the trade unions.

“We are determined and united to implement the necessary changes to secure the future survival and viability of Iberia.”

Under the latest proposal from Iberia, pay would have been cut by 23% for cabin crew and pilots and 11% for ground staff, versus an original target of 25% to 35% for all categories.

It also offered to shrink capacity by 10%, compared with the 15% that IAG says must now go, and early retirement and other incentives were on offer.

The failure of negotiations “poses a serious threat to the company, to Spanish institutions and to the tourism industry,” Manuel Atienza, a spokesman for the UGT union, told news agency Bloomberg.

Pilot representatives sought to defuse tension by urging talks at IAG’s headquarters, though the latest statement from the Sepla union said the most recent proposals from management were too tough.

It is thought that IAG could try to replace many of Iberia’s European short-haul flights with services run by the Barcelona-based budget carrier Vueling, which it is seeking to buy.

Iberia already owns 46% of Vueling and IAG in November launched a €113 million offer for the remainder of the company.