Cleary Gottlieb Steen & Hamilton has won a role to advise Ryanair on competition aspects of its latest bid for Irish aviation rival Aer Lingus.

Ryanair, which already owns 30% of Aer Lingus, has made a new offer which values the airline at €694m (£560m).

Arthur Cox chairman Eugene McCague is advising Aer Lingus on the corporate aspects of the bid, alongside Dublin corporate partner Stephen Hegarty, while regular adviser A&L Goodbody is representing Ryanair on corporate law, with John Given leading the firm's team.

The bid comes just days after the long-contested competition issue surrounding Ryanair's existing stake in Aer Lingus was referred by the Office of Fair Trading (OFT) to the Competition Commission.

UK and European authorities have been investigating the stake since the deal completed in 2006 amid concerns that it could hamper competition for passenger air travel between the UK and Ireland, claims which Ryanair disputes.

Cleary's team is being led by City and Brussels-based partner Nicholas Levy, while Covington & Burling is advising Ryanair on the competition dispute over the existing stake, led by Brussels antitrust partner Georg Berrisch.

Meanwhile, Cadwalader Wickersham & Taft competition partner Alec Burnside is continuing to represent Aer Lingus on the competition aspects of the existing stake, flanked by Linklaters' Eamonn Doran.

The OFT commenced an investigation into Ryanair's stake in Aer Lingus in October 2010 but the process has been delayed several times, most recently due to a legal challenge by Ryanair which was dismissed by the Court of Appeal in May.