The deal, which comes into effect immediately, follows a trial at several Londis stores over the past six months. Under the agreement, which runs until 2014, ADM will gain exclusive rights to Nisa's Heritage and Value own-label brands and the Nisa-Today's fascia in the Republic. Nisa will initially supply 10% of ADM's volume, worth 25m, but that percentage is expected to increase.
Nisa would stop recruiting new members, said Nisa-Today's chief executive Neil Turton, adding that the deal represented a major shift in strategy for Nisa in the Republic.
The company had been considering opening its own depot but, by signing up ADM, it could deliver directly to the retailer's depot in County Kildare and take advantage of its existing supply chain, he said.
ADM Londis commercial director Peter Foley said the deal would enable the company, which is the Republic's third largest symbol group, to offer more competitive pricing.
"We have identified savings of more than 10% on some products," he said. "The Londis franchise is now a more attractive proposition for symbol store operators given our enhanced buying muscle and commitment to a retailer-driven business."
The 20 large independent stores in Ireland Nisa supplies directly will be unaffected by the deal.
Meanwhile, Turton said the majority of Nisa's retail members had supported its decision to reject takeover approaches from logistics giant Bibby Line Group.
"Every member of Nisa has the same information on the bids as the board," he said. "The majority of members feel we got it right. If anything, some suggested that we should have been stronger in our rejection."
Bibby had requested details of all of Nisa's members but Turton said that so far it had not made any attempt to contact them.