Minister for Agriculture Simon Coveney has said he did not think QK Meats had broken the law but said he was "very unhappy with the way they've been operating".

Mr Coveney was speaking this morning after an investigation into the horse meat scandal branded the Naas company’s behaviour as “inexcusable” after it failed to inform the Department of Agriculture about positive DNA test results.

Yesterday he published the "hard- hitting" report which criticised QK Meats, named as the supplier of horse meat found in two Birds Eye products.

“QK Meats, knowing that the State was involved in a full public investigation into the source of equine contamination during the latter part of January, failed to inform the department of its earlier findings following positive DNA test results,” the report stated.

“Failure on their part to act at a much earlier time was inexcusable.”

The report said QK Meats senior management showed “scant regard” for the public good and “serious failure of judgment” by not revealing to the authorities information that could have shortened the initial phase of the investigation in identifying the likely source of the equine DNA.

QK Meats had been testing for equine DNA because "they clearly suspected that the product that they were importing wasn't of a quality it should be", Mr Coveney told RTÉ'S Morning Ireland . He added the department was unaware of QK's suspicions "because they didn't tell us".

The plant remains under investigation. The report found no evidence that Co Monaghan’s Silvercrest, which produced a burger containing 29 per cent horse meat, and Rangeland Meats, where tests that found some samples contained between 5 and 30 per cent horse meat, knowingly purchased or used horse meat in the production of beef products.

“ However Silvercrest itself has admitted that it had used non-approved suppliers in breach of specifications laid down by some of its major customers,” the report stated.

The failure of Silvercrest and ABP management in this regard and the “inherent disrespect” for customer requirements had led to very serious consequences not just for the company concerned but had also put at risk the reputation of the entire agri-food sector in Ireland, according to the report.

“ Silvercrest is owned by Ireland’s largest beef-processor, ABP. It is a real concern that management oversight and corporate governance structures were not in place to prevent the failures detected in this investigation in Silvercrest.”

The report concluded that no issues had arisen in the investigation in respect of Liffey Meats, ABP Nenagh and Dawn Fresh Foods.

In the case of B&F Meats, consideration of institution of legal proceedings for possible non-compliance with labelling regulations is under active consideration.

Meanwhile, a section of the report is devoted to Ossory Meats, an equine slaughter plant based in Banagher, Co Offaly, where the department carried out identification checks on horses presented for slaughter last Friday.

A total of 25 of the horses presented had “irregularities” related to passport and microchip identifiers. In some cases, while the microchip in the equine matched the passport, the marking on the horse and the passports were very different. In other cases horses presented as yearlings were in fact much older. The company has since been suspended from operations.

The incident was described as “quite extraordinary” in the report, “particularly the brazenness in attempting to have these animals slaughtered at a time when controls had been enhanced in the plant in question and also when the entire horse meat saga was receiving such intensive public scrutiny”.

Separately, the report said equine DNA found in consignments of frozen beef products in Ireland was labelled to be of Polish origin. The investigation did not find evidence of the adulteration with horse meat of these consignments in Ireland.

In some cases the investigation has revealed direct trade with Poland. In the case of one Polish company whose product was found positive for equine DNA, the company arranged to collect the consignment and to reimburse the Irish operator, which was QK Meats.

The report's title is Equine DNA & Mislabelling of Processed Beef Investigation .