After 26 years with the group and 15 years as chief executive, Mr Pat O'Neill is to retire as chief executive of Avonmore Waterford Group at the end of March. He will be succeeded by the chief executive designate, Mr Ned Sullivan.

Mr O'Neill's plan to retire and Mr Sullivan's appointment as his designated successor was first disclosed by AWG last year, but Mr O'Neill's decision to retire at the end of March comes 15 months sooner than was indicated last year.

Mr O'Neill said he made his decision to retire next month because the merger between Avonmore and Waterford has progressed smoothly and because the subsequent reorganisation will be completed by next June.

"It will be a seamless transition," he said of the hand-over to Mr Sullivan. "It's an appropriate time to hand over."

As well as retiring as chief executive, Mr O'Neill will also be retiring as a director of AWG. He is already a non-executive director of Irish Permanent - which is in the process of merging with Irish Life - and the Campbell Bewley Group. He said yesterday that he may take on a small number of other directorships but also intends to act as a "mentor" to start-up and small companies.

Mr O'Neill joined the then Avonmore Creameries from the Irish Dairy Board in 1973 and became managing director of 1984, four years before the co-op was floated on the Dublin and London stock markets.

Since he became managing director, Avonmore's sales have increased in size from £233 million to £2.37 billion as the group expanded rapidly, culminating in the successful merger with Waterford Co-op in 1987. During that period, employment has increased from 1,400 - all in Ireland - to 10,500 in Ireland, the UK and the US.

AWG chairman Mr John Duggan said: "Pat has done an outstanding job. He played a crucial role in bringing about the merger of Avonmore and Waterford in 1997 and in ensuring the smooth merger of these two organisations into a major international food group. The creation of Avonmore Waterford will be his lasting legacy."