British Airways owner International Airlines Group has made a 1.36 billion euro (1 billion pound) bid for Aer Lingus, but the deal is conditional upon winning support from Ryanair.

O'Leary said he expected that IAG would submit its offer before the end of June. But an EU competition probe could delay the decision by months.

"The EU approval I suspect would happen beforehand, because the IAG offer would be conditional on competition approval," O'Leary told Reuters in an interview, when asked if he would wait for the EU before deciding on the sale.

"The offer would remain open until the EU had given competition approval."

(Reporting by Conor Humphries, editing by William Hardy)