Taoiseach Enda Kenny gave his backing to under-fire Football Association of Ireland (FAI) chief executive John Delaney, but described the €5m loan from FIFA after the Thierry Henry handball as "extraordinary".
Mr Kenny insisted Mr Delaney's position is tenable but said the FAI should give a comprehensive account of how the association handled the loan payment, which was subsequently written off by FIFA.
"John Delaney should answer and will answer all of those questions. His position is tenable and I'm sure he will be able to answer any questions about this matter," the Taoiseach said.
Mr Kenny said there was no need for an Oireachtas Committee to investigate the payment as it did not involve taxpayer's money.
However, Mr Kenny said FIFA's brass plate company in the Irish Financial Service Centre (IFSC), which had a €112m turnover before it was dissolved, should be investigated.
"I note the comments from John Delaney that the position in so far as the company that was in the IFSC here with a number of directors in the FAI should be investigated," he said.
Transport Minister Paschal Donohoe also said Mr Delaney had his support. Mr Donohoe said he spoke to the FAI boss about the payment and was assured the association would provide a detailed explanation for how the money was handled in the organisation's accounts.
"I support John Delaney and the work the FAI does but alongside that there are important matters that are of interest to the public and it is important that they are answered and dealt with in a comprehensive manner," the minister said.
Mr Donohoe said he was confident that all payments to the FAI and other sporting organisations from the Irish Sports Council were appropriate and made with proper oversight.
Fianna Fáil sports spokesman Timmy Dooley called on the FAI to explain the payment urgently as the controversy has the potential to damage the country's reputation internationally.
"The fact that news is only officially emerging at this time, in the context of a wider story about corruption, graft and secret payments at FIFA contributes to a sense of unease and has the potential to do enormous damage to our reputation," Mr Dooley said.
Sinn Féin's Dessie Ellis said Mr Delaney should come before an Oireachtas Committee and answer questions on the payment.