Around 700,000 of these eggs have been sent to the United Kingdom from Dutch farms - far higher than the 21, 000 first estimated.
The Department of Agriculture, Food and the Marine said it carries out tests on egg samples for fipronil as part of its annual residue testing programme.
It comes after the agency said on Monday that a "very small number" of eggs distributed in Britain were believed to be from affected farms and that the risk to the public was "very low".
The European Commissioner in charge of food safety called Friday for an emergency meeting of ministers to discuss eggs contamination, appealing for an end to finger-pointing among member states over the scandal.
The investigation is being done by Dutch food safety authority NVWA's investigative department, on behalf of the Public Prosecutor.
"The Veterinary and Food Administration is following the issue closely, and can not exclude that further examination may uncover more imports of fipronil-tainted egg products to Denmark", it said.
Farms had been shut down in four countries - Belgium, Netherlands, Germany and France - where authorities have confirmed the illegal use of the substance to treat poultry farms, he added.
FSA chairman Heather Hancock said she was "confident" that acting quickly was the right thing to do. Fipronil can be hazardous to humans' kidneys, liver and thyroid glands, according to the World Health Organization, but only if consumed in large quantities.
Several producers in the Netherlands and Belgium are under investigation after eggs there were found to have been treated with a product containing pesticide Fipronil. "The Food Standards Agency and Food Standards Scotland are committed to ensuring that food is safe, and that United Kingdom consumers have food they can trust".
Similarly, early last month, a small quantity of liquid pasteurised egg - with a "use-by" date of July 20 - was supplied to a number of food businesses for use in bakery products, the FSAI added.