Pig farmers are calling for the growing population of wild boar to be culled in order to prevent the spread of disease and cross-breeding.
French pig farmers have had problems with wild boar
With increasing numbers of pigs kept outside, the National Pig Association warns wild boar are breaking in and intermingling with farm-kept pigs.
The Department of Environment, Food and Rural Affairs is conducting a review.
But NPA spokesman Ian Campbell warned wild boar can harbour classical swine fever and foot-and-mouth disease.
"We have been pressing the vets within Defra that they should be monitoring the small wild boar populations that have established themselves," said Mr Campbell.
"We would be extremely concerned if they were to spread out
of their existing pockets and on that basis, regrettably, would prefer
to see them culled," he added.
"One of the main problems is that wild boar harbour classical swine fever and foot-and-mouth disease and we have seen problems with this on the Continent," he said.
There is also a cost issue as any cross-bred piglets would not be eligible for sale.
Pigs have to be kept on fresh ground each year so it would also be costly for farmers to build impenetrable fences every time their pigs are moved.
Pig farmers say their stock is being threatened
The Department of Food, Agriculture and Rural Affairs said it has begun talking to farming and countryside organisations, including the NFU, to get details of how feral wild boar affect agriculture and the environment.
The department is planning to draw up a wild boar management report by the end of March.
This will then be put out to consultation if the minister approves, a Defra spokesman said.
The culling call is supported by the Pig Veterinary Society as feral wild boars are a source of disease.
Society president David Chennells said: "Wild boar are quite capable of getting through any kind of barrier that is put up."
But, he added, it should be an organised cull carried out by trained marksmen.