Sinn Féin President Gerry Adams is appealing to Taoiseach Enda Kenny to intervene in the Ibrahim Halawa case.
It comes after the Egyptian parliament is reported to have rejected calls from the Irish Government for his release.
The Dubliner has been held in an Egyptian prison, without trial, for nearly three years.
Mr Halawa (20), who is from Firhouse, was arrested at a protest in Cairo in August 2013.
His hearing was postponed again last month - the 14th time the mass trial has been delayed.
The next court date has been set for October 2nd.
Mr Adams has welcomed news that lawyers acting on behalf of Mr Halawa are to submit a new application for an Egyptian Presidential decree, in spite of comments made in the Egyptian parliament.
Mr Adams said: "Ibrahim Halawa, a 20-year-old Irish citizen, has now spent over 1,000 days incarcerated in a filthy and over-populated Egyptian jail. His trial has been postponed an astonishing 14 times and he has detailed the ill-treatment and torture he has faced, as well as what other prisoners have been subjected to. It is despicable."
"The Government's strategy to date, although very well intended, in attempting to secure his release has been unsuccessful and I would again today appeal to Enda Kenny to exert pressure at the highest levels in Cairo to secure Ibrahim’s release."
TDs and Senators last month passed a motion calling for Ibrahim to be released.
According to BBC and Daily News Egypt, however, Egypt's House of Representative has said Ireland cannot interfere "in the affairs of the Egyptian judiciary".
The speaker of the Egyptian parliament, Ali Abdel-Aal, read a statement on Sunday accusing Mr Halawa of being a member of the Muslim Brotherhood. This has been denied by his family.
Egyptian politicians were also told Mr Halawa is charged with "assaulting police, disrupting roads and endangering the safety of citizens".
'No prospect' of a fair trial
In a statement, Darragh Mackin, Ibrahim's solicitor, said the legal team has not yet received any direct communication or confirmation from the Egyptian government over the reports.
"The basis for the objection seems to be twofold," he explained. "(1) that Ibrahim is currently accused of serious criminal offences and (2) that to release him would interfere with the separation of powers between Government and Judiciary.
"There is no hiding from the fact that such a politically charged statement is concerning, and unconstructive, in working towards Ibrahim’s release. It is however a political statement, and has no basis in law, nor is it a direct response to the application for Ibrahim’s release," he added.
Mr Mackin said there is "no prospect" of Ibrahim receiving a fair trial, and that his legal team will be asking the Egyptian Attorney General to petition the country's president for Ibrahim's immediate release under Egyptian Law 140 - which allows foreign defendants to be repatriated back to their country of origin before sentencing.
Meanwhile, the Green Party Leader Eamon Ryan expressed disappointment at the news.
But he also welcomed a move for an exchange of visits between the two countries on the case.
"The unanimous request of the Oireachtas was for the immediate release of Ibrahim Halawa, given that he has been imprisoned for so long without any conclusion to the trial process, or any evidence being presented against him.
"However, I welcome speaker Abdel-Al's agreement that constructive dialogue between our parliaments would take place and an agreement to an exchange of visits as part of the friendly relations between the two countries.
"We would hope to discuss inter alia democracy, human rights and the case of Irish citizen Ibrahim Halawa.
"In particular, we welcome the opportunity to visit Ibrahim in prison to speak with him, offer him hope and inquire after his welfare."
