A full commitment was required from all concerned to keep foot-and-mouth disease out of the State, the Minister of State for Agriculture, Mr Noel Davern, said.
He added that this required strict compliance with the ban on imports from the UK and the full co-operation of all those involved in the farming and agrifood sectors.
"The position is serious. We have not been infected since 1941. The UK commissioners have been informed of the imposition of the ban and a press release informing the public of the measures to be taken will also be issued today.
"The position will be reviewed by the standing veterinary committee on February 27th next, and if there is sufficient evidence, although that is by no means certain, Northern Ireland can be excluded from the scope of the ban."
Replying to a series of Special Notice questions, Mr Davern said it was not a "nod and wink" situation.
"It must be ensured that products originating in or coming through the UK are not tolerated. We are in constant contact with our Northern Ireland counterparts. We will not clear it until a certain item is clarified.
"Pigs were delivered to an abattoir and the lorry which delivered them also brought back other animals. Until the origin of the animals is cleared, a ban is being placed on Northern Ireland.
"The Border area is very difficult to patrol, and that is why extra people have been stationed there to ensure that every farmer in the area is extremely vigilant.
"There was a fantastic response in 1968 to the outbreak in England. Everyone was conscious of it."
He said the disease was highly contagious, particularly in pigs. If there was an outbreak in the State, the movement of clusters of people would also be restricted, particularly people from farms.