British Airways-owner IAG has offered concessions in an attempt to win European Union regulatory approval for its plan to buy Aer Lingus, the European Commission said today. 

The EU competition authority will now decide by July 15 instead of July 1 whether to clear the deal, according to a filing on its site. 

IAG submitted its concessions yesterday, the EU competition authority said on its website, without providing details.

"IAG's engagement with the Commission is ongoing, and it would be inappropriate to comment further at this stage," an IAG spokesman said.

Sources told Reuters last week that the Commission was unlikely to approve the stake buy without concessions from IAG to allay competition concerns. 

Airlines typically offer to give up airport slots, allow rivals access to connecting traffic or let competitors sell tickets on their flights on certain routes to secure regulatory clearance.

IAG's Aer Lingus bid is conditional on agreement from Ryanair, which has a near 30% stake in the former national carrier.

Earlier this month, IAG formally outlined its offer for Aer Lingus, which values the airline at €1.4 billion. International Consolidated Airlines Group said that Aer Lingus shareholders will receive €2.55 in cash for each Aer Lingus Share. 

This comprises a cash payment of €2.50 per Aer Lingus share and a cash dividend of five cent per share.

The airline said the offer will initially remain open for acceptance until 5pm on July 16.

The offer document promises to keep the airline's brand and head office in Ireland, boost connectivity and keep the Heathrow landing slots for seven years.

The Government, which has a 25% stake in Aer Lingus, said last month that it would support IAG's bid for the former national carrier. 

Minister for Transport Paschal Donohoe said the Government would receive €335m for its stake in Aer Lingus but will retain one share in the airline.