The animals may have been contaminated by animal feed
The Food Standards Agency will meet later to assess if Northern Ireland pork products are affected by a contamination outbreak in the Republic.
All pork products made in the Republic of Ireland since September have been recalled by the Irish authorities.
The action was taken after dioxins were found in slaughtered pigs thought to have eaten contaminated feed.
Tests showed some pork products contained up to 200 times more dioxins than the recognised safety limit.
Joe McDonald from the Ulster Farmers' Union said clear guidance was needed from the FSA in Belfast.
"This is a very, very important time of the year for pig farmers and it is very important the public are confident about the produce they are buying," he said.
"We want to make sure that this situation is dealt with very vigorously, and that there is clear guidance given to the public and that we deal with this a quickly as possible so that in the coming days we can restore normality."
The Irish Minister for Agriculture, Brendan Smith, said the problem was confined to 47 farms.
"This includes 38 beef farms," he said.
"This is the total number of farms identified as having received possible contaminated animal feed. There is only one feed supplier involved."
The FSAI's chief executive Alan Reilly said: "The levels in the feed were very high. The levels in the pork itself were in the region of about 80-200 times above the safe limits."
Padraig Walshe, president of the Irish Farmers' Association, described the recall as "an absolute disaster" at an important time of the year for the pig sector.
He stressed that fewer than 10% of the products on the market had been processed since 1 September.
About 7,000 people are employed in the Republic of Ireland's pig industry, including about 1,200 on farms.
Almost 500 farmers produce 3.6 million pigs annually, according to the Irish Agriculture and Food Development Agency.
The industry exports approximately 60% of its production and is worth more than 250m euros (£216m) a year.
The British Pig Executive said that between April-July this year, the UK imported 230,000 tonnes of pork and bacon, with up to 15,000 of those from the Republic of Ireland.
The UK's Food Standards Agency said it did not believe at this stage that UK consumers faced any "significant risk".
A spokesman said the agency was awaiting confirmation from the Irish authorities as to whether any of the affected products had been exported to the UK.
He said they would assess the situation and take any action required to protect UK consumers.
Consumers and retailers in the Irish Republic have been warned to destroy all Irish pork and bacon products bought since 1 September as a precaution.
Bacon, ham, sausages, white pudding and pizzas with ham toppings must be included in the withdrawal of stocks, the Food Safety Authority of Ireland said.
Dioxins are formed during combustion processes, such as waste incineration, and during some industrial processes.
The presence of the dioxin polychlorinated biphenyls (PCBs) - a substance banned in the Irish Republic since the 1970s - in animal feed and pork samples was confirmed on Saturday afternoon in test results from a UK laboratory.
Chronic long-term exposure to the dioxin can have serious health effects, including causing cancers, but Irish officials said the recall would ensure consumers only had minimum exposure to it.
The country's chief medical officer, Dr Tony Holohan, said anyone who had eaten pig meat did not need to seek medical help.
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