Attempts to build millions of euro worth of business deals between Ireland and Egypt could be blocked unless the Ibrahim Halawa case is "satisfactorily" resolved,.
Dáil Ceann Comhairle and Fianna Fáil TD Sean O Fearghail made the comment before flying to the middle eastern country with a cross-party group of TDs for a series of high-level meetings with Egyptian president Abdel Fattah el-Sisi and other officials.
The week-long visit - which will also see the Irish delegation tomorrow meet directly with Mr Halawa, who has been held in a Cairo jail without trial since August 2013 - has been organised to allow face-to-face discussions over potential future bilateral deals on communications, agriculture, trade and tourism.
However, speaking on RTE Radio's Morning Ireland programme, Mr O Fearghail said any potential agreements could be blocked or scrapped entirely unless Egyptian authorities resolve the case of Ibrahim Halawa amid ongoing concerns over the now 20-year-old Irish-Egyptian citizen's treatment.
"At each of those meetings we will be talking about the Ibrahim Halawa issue and seeking to have it resolved. On Tuesday we hope to meet directly with Ibrahim and hear from him the story of his three-year incarceration.
"It's inevitable that there's a connection [between Irish-Egyptian deals and the Halawa case], it's like the stone in our shoe of building relations, but it's through building those relations that I think we can negotiate a resolution to this particular problem," he said.
"The key point here is this [Ibrahim Halawa] is a young Irish citizen, a person who was a child in Irish law at the time the events occurred in Cairo, and three-and-a-half years is an inordinate amount of time for him to have been in jail without going before the courts, and we will be highlighting that to the Egyptian authorities at every opportunity.
"I think it will be clear to anybody we meet that the full fruition of relations between our countries will depend on the satisfactory outcome to the Ibrahim Halawa issue.
"In order for there to be an enthusiasm on the part of the Irish authorities and Irish people to build on those [potential business and trade] connections with Egypt, it is inevitable that the Ibrahim Halawa issue will have to be resolved," he said.
Ibrahim Halawa was arrested during a protest in Cairo in August 2013 over the then president Mohamed Morsi's removal from power.
While he has been charged and jailed alongside 100 other people over alleged incidents related to the Muslim Brotherhood, no evidence has been provided to support the claims, with 16 planned court dates being suspended since August 2013.
Although Taoiseach Enda Kenny and Foreign Affairs Minister Charlie Flanagan have made a number of requests for Egyptian authorities to resolve the case, opposition parties have criticised Government for a failure to act on the issue.
In addition to meeting with Egyptian president el-Sisi, the Dáil cross party group - which also includes Fianna Fáil foreign affairs spokesperson Darragh O Brien, Fine Gael TD Colm Brophy, Labour leader Brendan Howlin, AAA-PBP TD Paul Murphy, Sinn Féin TD Eoin O Broin, Green party leader Eamon Ryan and Independent TD Noel Grealish - will meet Egyptian government officials and representatives of the Arab League.