The firm recalled chocolate in June last year due to potential Salmonella from the ingredients used in making them at a plant in Slough, UK.
Two pallets of Galaxy Smooth Milk bar (42g) and Maltesers Fun Size bags were on hold with an Irish distributor awaiting destruction but were instead placed on the market.
Galaxy has batch code 720B1SLO00 and best before 13.5.2018 while Maltesers has batch code 720A1SLO00 and best before 13.5.2018.
Mars Ireland said: "We were notified that our third party logistics partner had, in error, dispatched some product that we had isolated for destruction.
"We are continuing to work closely with FSAI and our retail customers to ensure that the impacted products are not available for purchase.”
Consumers are advised not to eat the specific batches. Consumption could cause salmonellosis but there are no reports of illness.
Mars added no other brands or varieties of chocolate, pack formats, bar sizes or best before dates are affected in Ireland.