"NorgesGruppen has received final confirmation today, Friday February 15, that lasagnes (sold under the First Price brand) contained horsemeat," it said in a statement.
"NorgesGruppen immediately withdrew the First Price lasagnes from its stores' shelves at the end of last week after doubts arose about the use of horsemeat in European food production," the company said.
Supermarkets across Europe have pulled millions of frozen ready meals from the shelves since last week, after tests revealed that large quantities of horsemeat had made their way into products labelled as beef.
The French government on Thursday said the French firm Spanghero knowingly sold around 750 tonnes of horsemeat as beef, including 550 tonnes to French company Comigel which makes frozen food, and that it was suspending the licence that allowed it to handle meat.
The dishes found to contain horsemeat in Norway had been prepared by Comigel, a spokeswoman for NorgesGruppen, Kine Soeyland, told AFP.
Falsely-labelled meat has been found in Britain, France, Germany,Switzerland, and now Norway.
NorgesGruppen is Norway's largest retailer, with chains like Kiwi, Meny,Joker and Spar, as well as upmarket stores such as Centra, Ultra and Jacob's.
On Wednesday, Norwegian food safety authorities said ready made meals by frozen food giant Findus thought to contain horsemeat instead of beef had been pulled from supermarket shelves.