Aer Lingus chairman, Mr Bernie Cahill, has died in a drowning accident close to his home in Schull, Co Cork.
According to Garda sources, Mr Cahill went to a pier not far from his home to secure his yacht, which was moored there, shortly before 8 p.m.
A passer-by noticed a body in the water some time later.
When gardaí were called to investigate, they discovered Mr Cahill's body floating in the water near his yacht.
It is understood that the wind had strengthened and that Mr Cahill was concerned about ensuring that the yacht was safely tied up.
It is understood that attempts were made at the scene to resuscitate the businessman, but it is understood that he was pronounced dead on arrival in hospital.
A post mortem is due to be carried out tomorrow.
The Minister for Public Enterprise, Ms O'Rourke, tonight extended her "deepest and fullest sympathy" to Mr Cahill's wife and family.
A spokeswoman said: "On behalf of the Taoiseach and of the Government, Ms O'Rourke paid tribute to Mr Cahill's long and distinguished career in the public service."
An Aer Lingus spokesman described Mr Cahill's death as "a tragic loss to the airline".
Mr Cahill, an internationally respected businessman, has held the Aer Lingus post since 1991, he is credited with restructuring the airline. He held the post of executive chairman for some time. He also led Greencore, the former Irish Sugar company, to the market.
Mr Cahill is survived by his wife and three children.