The trial of Irishman Ibrahim Halawa in Egypt was put back again this morning, for the 13th time.
A new trial date of 26 June has been set.
The now 20-year-old from Dublin was arrested by the Egyptian army as he took refuge in a Cairo mosque while Muslim Brotherhood protesters staged a "day of rage" outside in August 2013.
Gavin Booth of Kevin R Winters Solicitors in Belfast, which is acting for the family, has said the UN has now joined the European Parliament in calling for the immediate release of Mr Halawa and has called on the Government to alter its position to call for his immediate release.
Outgoing Minister for Foreign Affairs Charlie Flanagan expressed his "deep concern" over the further delay in Mr Halawa's case.
"The constant adjournments in the case are, understandably, a source of concern and frustration for Mr Halawa and his family, and I share their deep disappointment at today's news," he said.
"Ireland's Ambassador to Egypt Mr Damien Cole was once again present in the court for today's hearing and spoke with members of Ibrahim Halawa's family following the adjournment.
"I want to reassure Ibrahim's family of my own and the Government's continued commitment to achieving our two objectives: to secure his return to Ireland as soon as possible and to ensure his welfare during his detention.
Amnesty International has criticised Egypt for the continued postponement of the trial.
Previously the human rights organisation said Egypt "continues to flout international human rights laws with the continued detention of thousands who dared to peacefully protest".
Politicians have waded into the issue with the Green Party and Fianna Fail condemning the latest postponement of the trial.
Green Party leader Eamon Ryan said: "The tragedy continues to unfold for Ibrahim and his family. He has to go through all of this again at the end of June. The waiting and hoping are truly devastating for this young man.
"No evidence has ever been presented against Ibrahim. Amnesty International, Reprieve and other human rights organisations have continually demonstrated his innocence."
Fianna Fáil Spokesperson for Foreign Affairs Brendan Smith said: "It's unacceptable that an Irish citizen, who was aged just 17 when taken into custody, is being denied a fair trial.
"The Government needs to step up its efforts with the utmost urgency to secure the release of Ibrahim as it is evident he is not being afforded a fair trial."