Independent TD Michael Lowry has claimed that a multi- million euro investment in a Tipperary hospital is linked to representations he made to the Fine Gael minority Government.
Fresh questions have been raised about Mr Lowry's relationship with the Government following the end of last week's court case in which he was fined for tax offences.
Mr Lowry has previously said he has an "understanding" with Fine Gael, though this has been denied by the Government.
Now the Tipperary TD has said Leo Varadkar called him seeking his Dail vote to become Taoiseach last year.
In an interview, he said he told Mr Varadkar he would have his "unconditional support" as the country needed stability.
"I didn't say 'I'm voting for you on the condition that you do X, Y or Z'," he said.
"I gave him unconditional support and in the course of that conversation what I did say was that we have a problem in my constituency that needs attention."
Mr Lowry said one of those problems was at South Tipperary General Hospital in Clonmel, and he now claims that there has been an investment there to add more beds as a result of representations he made.
A spokesman for Mr Varadkar said: "As Deputy Lowry has confirmed, the deputy neither laid down any conditions nor sought any concessions linked to his general support for the Government. There is no formal agreement with him, written or otherwise.
"Along with other Independent TDs who broadly support the Government, he often raises constituency issues with ministers or the Taoiseach's office and we will work on them where they are good policy and make sense, as is the case with any good policy."
In relation to the hospital, the spokesman said: "Clonmel is one of around 12 hospitals where capacity is being increased and has a major overcrowding problem in winter.
"It should be noted that Deputy Lowry has voted against the Government on 10 occasions, including on the Road Traffic Bill, so his support is general."
Meanwhile, Fianna Fail has responded to Mr Lowry's claim that it is "a bit rich" for party leader Micheal Martin to raise questions about arrangements he may have with Fine Gael.
Mr Martin challenged Mr Varadkar to publish details of any assistance given to Mr Lowry, during a debate in the Dail last week.
Mr Lowry said he had written agreements with previous Fianna Fail governments and said Mr Martin would have known about them.
He said: "It's a bit rich that he is unhappy now".
Last night a Fianna Fail spokesman said that "previous government deals with Deputy Lowry were on the record and included other Independent deputies".
He repeated Mr Martin's call to Mr Varadkar to publish details of any assistance to Mr Lowry "in the interests of transparency".
Mr Varadkar insisted in the Dail that there is "nothing to publish and nothing to hide", and there is no formal agreement written or verbal with any Independent TD.