A consignment of meat being held in quarantine by Freeza Meats was tested and found to contain 80% horsemeat on Monday.
The Newry firm said it had been storing the meat, which was from Poland, in its cold store as a goodwill gesture after refusing to buy it from trader McAdam Foods, based in the Republic.
The meat never entered the local food chain.
Asda said that while no horse DNA has been found in burgers supplied by Freeza, it has taken them off the shelves as a precaution.
A statement said: "Asda sources four frozen burger products from Freeza Meats in Northern Ireland. It's important to note that both the local EHO in Northern Ireland, and our own independent DNA tests have come back free of any trace of horse meat.
As a precaution we have taken all four frozen burger products off sale produced in that factory, and have instructed Freeza Meats to segregate and hold any frozen burgers currently in production or in their supply chain destined for Asda
"Although all the science says there is no trace of horse in our burgers produced by Freeza Meats, we can't and won't take any chances when it comes to the authenticity of ingredients in our products."
The burgers removed by Asda include its four pack of 100% beef quarter pounders, four pack of beef quarter pounders, eight pack of beef burgers and four pack of big eat burgers.
Freeza Meats, which employs more than 45 people, is a specialist in burgers for the catering industry in Britain and Ireland.
Director of the family-run business, Paul Mackle, has previously told UTV he was shocked and angry about the situation, which he believes could force them to shut.
"We are still coming to terms with it," he said. "We can't believe we are in this situation through no fault of our own, doing a good turn for somebody. We made sure that it was kept separate."
Newry and Mourne District Council's Environmental Health Department confirmed the suspect meat consignment had been detained for the last five months "due to the condition of its wrapping and queries regarding its labelling and traceability".
On Tuesday John Farrell, the council's Director of Environment, Health & Building Services, said Freeza Meats was put in a difficult position "through no fault of their own".
"Freeza Meats had meat in their cold store that they could not move because we had officially detained it and it was up to us to have the meat removed to its owner, put into pet food or destroyed," he said.
Meanwhile McAdams Foods, based in Co Monaghan, said it is shocked and astonished that horsemeat was found in meat it imported, and is co-operating fully with authorities.
A company spokesman said: "The source of these products is Polish and McAdam Foods has identified the specific Polish supplier names to the Irish authorities.
"McAdam Foods is co-operating fully and willingly with the authorities.
"We are confident that the documentation and proof that we have provided to the authorities will fully exonerate our company."
It has also emerged that the Bureau of Criminal Investigation is assisting the inquiry team into the horsemeat scandal, after the Food Safety Authority said they believed there was an element of fraud surrounding the contaminated beef products.
Garda Commissioner Martin Callinan said they are not investigating anything specific at this stage but are helping the FSAI and Agriculture Department.
Mr Callinan continued: "We would hope for everybody's sake that it would be a very short investigation and that, collectively or individually, we would get to the root of the problem to deal with it as quickly as possible - that would be the desirable outcome."
Polish officials have now written to Ireland requesting proof that the contaminated produce is linked to Poland.
Dr Janusz Zwiazek, chief veterinary officer, asked for photos of labels and test results.
He said they have carried out inspections at slaughter houses and factories and found no evidence of horse DNA and said there is no evidence of falsified labels.