The Progressive Democrats have confirmed they received two separate donations of £50,000 in the past year from Treasury Holdings and Ryanair chief executive Mr Michael O'Leary.
The party will declare to the Standards in Public Office Commission that they received the two donations worth £100,000 (€126,974) that are disclosable by law under the Ethics in Public Office Act for last year, according to a party spokesman.
Last week, the PDs said they wanted the amount of cash given to them to remain secret until next month. A party spokesman said then that details of funding referred to by the Tánaiste, Ms Harney, during a Cabinet discussion the previous week, would be revealed by the Commission in its annual statement of political donations due for publication in the middle of March.
It was not intended to disclose the size of the donations by any other means, the spokesman said. "There is a legislative framework for disclosure of donations and we comply with that. All details will be given in March."
However, a report in yesterday's Sunday Tribune gave details of both donations, which the party say were "fully transparent" and "in line with the legislation".
Under the Electoral Act, political parties must declare all donations in excess of £5,000 (€6,349).
Ms Harney asked the Government secretary to put the matter on record during a Cabinet discussion on the decision to approve new facilities at Dublin Airport for low-cost airlines.
Mr O'Leary has long sought to build a terminal for Ryanair's use at Dublin Airport in return for a concession on landing fees.
No such concession is available under the terms of the Cabinet decision and the new terminal will be built and controlled by Aer Rianta.
Treasury Holdings is one of the larger and more successful property companies in Ireland, with major developments under way such as the Central Park out-of-town office scheme in Sandyford.
It has been involved in controversy recently over a deal allowing the company to develop CIÉ's property at Spencer Dock in Dublin.