The Department of Foreign Affairs has said it is aware of the arrest of an Irish citizen in Rio, but cannot comment on individual cases.
Public Accounts Member and Fine Gael TD, Noel Rock, has said the OCI President's arrest is a "dark day for Irish sport" and said an external independent investigation is now needed.
Mr Rock said: "This is simply extraordinary and marks a dark day for Irish sport. It is a source of deep shame that it has come to this, and now the President of the Olympic Council of Ireland has been arrested. This is extraordinary and unprecedented, and casts a dark shadow over our Olympics".
He added: "For the last week it has been clear to anyone watching this that there were more questions than answers. I have consistently called for the OCI to come clean on this matter. I regret that more robust action was not taken sooner and this charade was allowed to go on for a week."
Shell shock here in Rio— Shane Ross (@Shane_RossTD) August 17, 2016
"The Irish public deserve answers as to what exactly is going on with the OCI, and I believe the Minister must now get them. The OCI receives a substantial portion of taxpayer funding, and answers are now both urgent and necessary.
"It is clear that Irish authorities must now engage with counterparts in Brazil to ensure that this is dealt with but it is equally clear that we must get answers on behalf of the Irish public," Mr Rock added.
There is a developing situation in Rio regarding the ticketing story. The OCI will only issue updated statements via its website.— Team Ireland (@TeamIreland) August 17, 2016
"I am now calling on the Minister to implement an external investigation of the OCI and all of its commercial dealings with immediate effect. This farce has gone unchecked for long enough," he concluded.