Frozen food company Birds Eye has said that an Irish meat processor supplied meat for two of its ready meals that tested positive for equine DNA.
In a statement, Birds Eye said QK Meats in Naas, Co Kildare had supplied meat to a Dutch company, which in turn made the meals for Birds Eye.
QK Meats has said it never knowingly incorporated horse meat into any of its beef products.
It said it has launched a full investigation into its supply chain.
On 22 February, Birds Eye withdrew three products from the UK and Ireland as a precaution, after horse DNA was found in one product sold only in Belgium.
Following tests, a Birds Eye spokesman said today that 5%-7% equine DNA was found in its spaghetti bolognese and beef lasagne.
He said that the company had removed a couple of thousand of the ready meals from Irish shelves.
It added in a statement that Dutch company Frigilunch NV, who supplied these products to Birds Eye, had received the meat with horse from QK Meats.
It added that Frigilunch's own independent tests had confirmed their findings.
ABP Food Group Chief Executive Paul Finnerty said some products that were produced for certain customers at the Silvercrest facility in Co Monaghan came from a combination of suppliers that were not approved.
Speaking at a House of Commons committee hearing into the horse meat scandal, Mr Finnerty said ABP knew nothing about this and all of its businesses were what he called clean with the exception of Silvercrest.
He said they were the victims in this and had been defrauded.
Mr Finnerty told the hearing that the contaminated product came from Poland.
However, he said ABP did not have evidence that it had been contaminated when it left Poland and added that the company was not in a position to give the names of individual suppliers.
He said the company in question has made a public denial.
Mr Finnerty apologised unreservedly to the committee for what happened at Silvercrest and said that ABP had never knowingly bought or ordered horse meat.
However, they had lost the Silvercrest contract with Tesco and the factory had been closed.
He said staff at Silvercrest were on paid leave until the company got to the end of the matter and number of managers have been stood aside.
On 15 January, the Irish authorities announced that horse meat accounted for some 29% of the meat content in a Tesco Everyday Value Beef Burger.
It was supplied by ABP's Silvercrest facility.
Dozens of companies across Europe have been caught up in the horse meat scandal.
The controversy has prompted widespread product withdrawals and government investigations into the continent's food processing systems.
Although horse meat poses little or no health risk, the discoveries have damaged the confidence of consumers in supermarkets and fast-food chains.