All consignments of live animals shipped to Northern Ireland from Great Britain in recent days are to be checked for foot and mouth, the province's agriculture minister said today.
Michelle Gildernew said officials were inspecting 65 consignments received since restrictions were lifted on August 23.
She has already returned one shipment after hearing of the suspected outbreak in Surrey this morning.
Export licences have been withdrawn for live animals and non-pasteurised dairy products and disinfectant mats placed at airports and ports.
The minister said local experts were examining the recent arrivals.
"All those inspections will be carried out by tomorrow, we have put the Fortress Ireland approach back into place," she said.
"We have been very decisive in our actions that we have taken in order to try to keep foot and mouth out.
"The steps I took were from a pre-emptive and precautionary point of view. We took them before there was confirmation of the outbreak."
She said she had consulted with senior colleagues, held meetings with Irish counterpart Mary Coughlan and was talking to the First and Deputy First Ministers the Rev Ian Paisley and Martin McGuinness this afternoon.
Joe McDonald from the Ulster Farmers' Union said it was a setback.
"We need to ensure that if this is an outbreak that we retain our foot and mouth disease-free status because that is crucial to ensuring that we don't bring it into Northern Ireland and that we keep our trade open with our export market," he said.
"It is important to get this right."
Ministers have spent weeks assuring consumers of Northern Irish meat and dairy products that they are safe.
Special exemptions were granted to the province following imposition of an EU-wide ban on exports of produce from the centre of the outbreak.
Despite this, shipments to Japan and Venezuela worth huge sums of money were threatened.
Ministers were praised the last time for their speedy response to the potential crisis.