Prime Minister Mette Frederiksen "grossly" misled Denmark when she announced that the country's entire mink population should be culled, a parliamentary commission has found.
In addition, the committee has concluded that the Danish government's actions in 2020 were "highly reprehensible".
Frederiksen had said that the country needed to kill around 15 million animals to prevent the transmission of COVID-19 variants.
But an investigation has found that she had no legal basis to issue the culling order, even though she may not have been aware of the legalities.
The committee's findings have opened the possibility for disciplinary cases to be brought against Frederiksen and several senior officials.
In 2020, Danish health authorities had warned that mutations of the coronavirus in mink could compromise the future efficacy of vaccines.
The government then abruptly approved an order to cull the country's entire population, devastating the largest fur industry in the European Union.
It was later revealed that the law only allowed Denmark to slaughter animals in an infected farm or region.
Millions of mink carcasses -- which had been rushed to two landfill sites -- were then dug up and incinerated due to pollution risks.
The scandal led to the resignation of Denmark's agriculture minister and raised questions over the government's handling of the pandemic.
The controversy was also heightened after it emerged that Frederiksen's text messages during the culling decision had been automatically deleted for apparent security reasons.
The Danish PM was summoned by the parliamentary committee to testify in December ahead of the final report, published on Thursday.
Frederiksen has acknowledged her "mistakes" but has maintained that she was unaware that there was no law that allowed her to impose her decision.
She has also reiterated that decision to cull the mink was "taken on the basis of a very serious risk assessment".
The parliamentary committee has said that it had no duty to say whether Danish government ministers had acted intentionally or recklessly.
The country's parliament will now decide on any further disciplinary action, including possible impeachment -- a rare occurrence in Denmark.