Updated: 17/07/17 : 07:18:15
Amnesty International says it is gravely concerned for the mental and physical wellbeing of Ibrahim Halawa.
The Dubliner appeared in court in Cairo yesterday, and heard that his case was is be further adjourned until next week.
Foreign Affairs Minister Simon Coveney said that the trial appears to be moving towards a conclusion.
However, Amnesty's Colm O'Gorman says his continued detention represents an inexcusable violation of both international and Egyptian law.
"There has been some progress, but that shouldn't in any way diminish the fact that a young Irishman has been illegally detained, without access to a fair trial for coming up to four years in Egypt, despite the fact that there isn't a shred of evidence to connect him to any of the serious charges that have been made against him," he said.
The judge said no further witnesses remain to be called in the trial.
The case will continue on next Tuesday, when the prosecution will present its final arguments.