Trading director James Wilson, who was part of the Archie Norman and Allan Leighton golden generation at Asda, is on gardening leave while a departure date is finalised, a source confirmed to The Grocer in the wake of reports last week in the Irish press.
Wilson, who joined four years ago from Musgrave-owned SuperValu, is expected to take over from veteran Dunnes food director Dick Reeves, who is set to retire later this year.
His exit marks the retailer's second senior defection to Dunnes in a month former operations and development director Sheena Forde quit to become Dunne's new head of buying and will be a major blow to Superquinn, which is struggling to cope with a national slump in retail sales.
The retailer has lost out to more price-led rivals in the downturn. Since 2005, when Select Retail Holdings bought the chain for 450m, its grocery market share has fallen from 8.4% to 6.7%.
The beefing up of Dunnes' management follows the departure last year of COO Andrew Street, the company's most senior non-family director.
It comes as market leader Tesco has extended its dominance to 27% of the sector, a lead of more than four points on Dunnes.