On Thursday, the Guardian newspaper reported that Findus had withdrawn its lasagne range from British supermarkets after being alerted to a problem by Comigel, the French manufacturer that supplied Findus.
The lasagne was labelled as beef but tests showed that it contained up to 99 percent horse meat.
In Sweden, Findus has withdrawn its single-portion 375 gram lasagne, but the company insisted that the product is not harmful.
Around 100 tonnes of Findus beef lasagne meals are sold annually in Sweden.
The biggest supermarket chain, Ica, has also removed its own-brand of "Ica basic" 400g lasange, since it comes from the same supplier as Findus's lasange and the company fears it may contain horse meat.
British authorities have said the Findus product is probably not dangerous but have ordered tests to determine whether it contains the common horse painkiller phenylbutazone, often known as bute, which is banned from entering the food chain.
Mary Creagh, the UK's shadow environment secretary, told the BBC that "it's vital that people... have confidence that food that they buy is properly labelled, legal and safe for them to eat."
Customers are being advised to bring back the ready meals to the shops.
Swedish food retailers Coop and Axfood have also withdrawn lasagne products suspected of containing horse meet.
Coop withdrew its 400 gram Coop Lasagne and Axfood withdrew 1 kilo packs of Eldorado Lasagne Bolognese, the 400 gram Willys Lasagne Bolognese and Hemköp's Lasagne Bolognese.
The company producing those ready-made meals has used meat from the same butcherer that provided horse meet for Findus' withdrawn lasagne.
Axfood has submitted samples for tests but the lab has not yet confirmed whether the products contain horse meet.