Traces of African swine fever virus have been found in meat products seized at Northern Ireland ports of entry.
The virus is not harmful to humans but could have a major impact on the local pork industry if it became established in pig herds here.
The virus can live for months in processed meat and is highly contagious.
The tainted meat was identified after lab tests were carried out on samples from the 300kg of illegal meat and dairy products seized from passengers arriving in Northern Ireland last month.
Department of Agriculture, Environment and Rural Affairs (Daera) chief veterinary officer Dr Robert Huey warned that bringing contaminated foods into Northern Ireland could have a serious impact on the local agri-food industry.
"The greatest risk is to our agri-food industry and our environment," he told the industry newspaper Pig World.
"Any introduction of pests, diseases and non-native species can have a potentially devastating impact.
"Ecosystems can be disrupted, with significant knock-on effects on agriculture and the local economy.
"Imports of meat or meat products, milk and other dairy products are banned from most countries outside the EU.
"There are also strict controls on animal products that can be brought in from the EU.
"It is always advisable to check the rules before travel and refrain from bringing back animal products or plants that might be carrying pests or disease.
"Illegal products will be seized and destroyed.
"Furthermore, anyone detected in possession of prohibited items risks prosecution and a fine.
"So, please, do not bring any of these products back to Northern Ireland."
According to Daera, the detection of "DNA fragments" of the virus does not pose a significant health threat to animals here, nor does it change the country's disease-free status.
But Zoe Davies, chief executive of industry body the National Pig Association, said the discovery of African swine flu traces at local points of entry showed just how vulnerable the UK pig herd was to infection.
"We have always maintained that the biggest threat to the UK pig herd is from infected meat products that are illegally brought in from infected regions that then find their way into the UK pig herd or feral boar population," she said.
"It is therefore critical that we do everything in our powers to keep infection out of the country.
"(This includes) clear warnings at ports and airports that make the risks and penalties from bringing meat into the country clear to everyone, as well as more proactive surveillance and seizure of illegal meat imports."
In China, a third of the pig herd has had to be culled because of the virus, which has also been detected in Belgium, Bulgaria and the Czech Republic.