Etihad Airways has confirmed that it has acquired a 2.9% stake in Aer Lingus.
The airline said the purchase reflected its desire to forge a commercial partnership with the Irish airline.
"Aer Lingus and Etihad are engaged in discussions which to date have focused on reciprocal code-share opportunities," said an Aer Lingus statement.
"Future discussions may explore additional commercial and cost opportunities to develop a closer working relationship in areas such as joint procurement.
"Aer Lingus views these discussions as a natural progression of its successful Greenfield cost reduction programme. There can be no certainty as to the outcome of these discussions."
Etihad Airways operates 10 flights a week from Abu Dhabi to Dublin and has carried more than 750,000 passengers between the two capitals, since it began flying the route in July, 2007.
It comes amid speculation that Etihad might be interested in purchasing the Government's 25% stake in the airline.