MR Fergus Finlay, programme manager to the Tanaiste, has described as "absolute bilge" accusations by Opposition spokes persons concerning the awarding of an advertising contract for the divorce campaign.
The contract was awarded to an agency which includes a brother of the Minister for Finance, Mr Quinn, among its directors.
Saying the accusations were "without foundation, good, bad, or indifferent", and that he was "getting more annoyed by the minute", Mr Finlay said he found he was in "particular difficulty" on the matter as it is before the courts.
Last night Mr Finlay said he had sought legal advice as to how far he could go in rejecting the allegations without being in contempt of court. He expected to have a directive from his lawyers today, he added.
Senior Government sources also insisted that the contract to QMP of which Mr Conor Quinn is a director was "only awarded after the most stringent adherence to set procedures and tendering".
The sources said a letter last May from Mr Conor Quinn to Mr Finlay seven weeks before the contract was awarded to QMP had been deliberately misinterpreted by the Opposition" to create a situation that does not exist".
It is understood the contract involved a fee of about £40,000.
Political interest in the correspondence from Mr Quinn to Mr Finlay followed evidence last week in the High Court challenge to the outcome of the divorce referendum by Mr Des Hanafin.
When asked why Mr Quinn should be writing to the Tanaiste's programme manager about a contract concerning the Department of Equality and Law Reform, sources said he was writing to express his anxieties in relation to certain things including his relationship to the Minister for Finance.
Fianna Fail and the Progressive Democrats had earlier yesterday sought an explanation as to how Mr Quinn seemed aware of his company's appointment early last May and was in contact with Mr Finlay about the matter.
In the High Court, evidence was given concerning a letter dated May 4th from Mr Quinn to Mr Finlay, in which he considered the possibility of adverse reaction to his relationship to the Minister.
The Fianna Fail spokesman on equality and law reform Dr Michael Woods, said he was also "amazed" that a contract should be awarded by the Government to a company that stated in a memorandum that its strategy involved being "a bit liberal with the truth" on a claim that divorce would change nothing other than allow a spouse to remarry.
He also demanded that Mr Spring say whether he knew or agreed, before May 4th, to QMP getting the contract, even though the Government procedures were not completed for several more weeks.
"Was the Tanaiste made aware of, or shown the contents of the letter of May 4th from Quinn in which he wanted his connection as brother of the Minister for Finance `buried'" Dr Woods asked.
The Progressive Democrats equality and law reform spokeswoman, Ms Helen Keogh, claimed the letter raised serious issues of public accountability and displayed the Government's "brazen lack of transparency".