The last passport application approved by the Rainbow government was for a "substitute" investor whose name was ratified by the Cabinet on its final day in office after the original investor withdrew.
This ran contrary to civil service advice at the time that each applicant should be treated as new and that names could not be substituted.
The application was also submitted after the cut-off date of September 4th, 1996, which should have rendered it invalid.
The passport was awarded to a foreign investor in Briody Bedding, Oldcastle, Co Meath, which is in the constituency of the Fine Gael leader, Mr John Bruton, who was Taoiseach at the time. The firm now employs almost 100 people manufacturing beds. The passport was one of a number approved by the Rainbow coalition before leaving office in June last year - contrary to a Cabinet decision in September 1996 that no new application should be taken until the controversial naturalisation for investment scheme was put on a statutory footing.
However, in the case of Briody Bedding, the Cabinet decided to grant a passport to a person from Hong Kong who was not the original investor proposed for the company.
The Cabinet approved a proposal from the then minister for justice, Mrs Nora Owen, that the Hong Kong investor could "substitute" for the US investor who was no longer prepared to wait for a passport.
According to clear advice from the Department of Justice, each application should be treated afresh and there should no substitution of one name for another.
The original application for Briody Bedding was made in October 1995 and was approved. However, it is understood that when the person had not received the passport by the following August, he did not remain involved and the company, though approved under the scheme, was left without an investor.
The "substitute" investor then came forward. His name was put to Cabinet for approval on June 25th, 1997, the day before the Dail elected the present Government. The outgoing Rainbow Cabinet agreed he should get the passport provided he met all the conditions laid down, including the purchase of a home in Ireland.
A spokesman for Mr Bruton said the Fine Gael leader had received representations from the company in April 1997. His private secretary had forwarded the correspondence to the Department of Justice with a request that it be examined.
"The former Taoiseach's involvement in all these matters was a hands-off approach. As a matter of routine his office passed the letter of representation to the private secretary to the Minister for Justice, asking the Minister to look into this as a matter of urgency," the spokesman said.
It is understood this investor has not yet been issued a passport and that the company has not yet received any of the investment.
The naturalisation application is still being processed in the Department, along with about 30 awaiting finalisation.
Mrs Owen said she had fulfilled all the conditions of the passports-for-investment scheme as it existed at the time.
"This particular (Briody) case was in the pipeline when the Government decided on September 4th, 1996, to accept no new applications. I then left office and it was up to the Department to ensure the investor fulfilled all the conditions," she said.
Fine Gael has consistently called on the Government to publish the review into the passports-for-investment scheme.