The North's First and Deputy First Ministers have called an emergency meeting of the Northern Ireland Executive today to discuss the foot-and-mouth crisis.
The announcement came as the North's Department of Agriculture yesterday officially confirmed the first case of the disease at a farm in Meigh, Co Armagh.
The infected sheep were incinerated on Wednesday night, and a 3km protection zone has been established within a 10km surveillance area.
A livestock importer was arrested by the RUC in Banbridge yesterday at the request of the Department of Agriculture. The man was released after questioning.
Investigators are attempting to trace the movement of infected sheep from Carlisle market in the north of England to south Armagh and subsequently into the Republic.
The movement of the animals is understood to be in contravention of the licensing stipulation for immediate slaughter.
In a statement issued through his solicitor last night, the owner of the farm on which the disease was detected in south Armagh, Mr Maurice Collins, said he was co-operating fully with investigators. He had given "full details of the persons involved with the sheep" and denied that he had "gone to ground".
Pigs located at a unit adjacent to the Collins farm were incinerated yesterday as vets began inspecting animals on other farms in the area.
Suspect sheep at a farm in Castlederg, Co Tyrone, were tested yesterday, but it is understood the animals have shown no further symptoms, and vets believe it is not a further case of the disease.
Mr David Trimble and Mr Seamus Mallon are today expected to announce the establishment of a special inter departmental committee to tackle the crisis.
A spokesman said the emergency Executive meeting would allow the North's Minister of Agriculture, Ms Brid Rodgers, to brief Ministers on the situation.
Ms Rodgers yesterday denied that the exclusion zone in south Armagh was not being maintained. She said she did not wish to place restrictions on the movement of people. "But if necessary I will", she added.
The chairman of the Stormont Agriculture Committee, the Rev Ian Paisley, described the crisis as a tragedy which should not have happened.
"If there are people to blame, then they have to take the blame", Dr Paisley said. He has called for an inquiry into why sheep licensed for slaughter ended up on the south Armagh farm.
Commenting on the confirmation that the disease had arrived in the North, Mr Alasdair MacLaughlin, of the Ulster Farmers' Union, predicted that the effects on the industry would be "huge".
"Not only is it a matter of the destruction of individual herds, but there are implications for the entire industry. It will close down trade", Mr MacLaughlin said.