Minister for Foreign Affairs Charlie Flanagan has expressed concern that the trial of Ibrahim Halawa in Egypt has once again been delayed.

A court hearing in the mass trial of 494 people, including the 19-year-old Irish citizen, has been postponed for a fourth time.

The group was arrested in a crackdown on protests in the Egyptian capital in August 2013.

According to reports from the makeshift courtroom in Tora prison, the judge postponed the trial until 29 March.

The authorities said proceedings will be moved to a specially-adapted courtroom outside Cairo.

Speaking this afternoon, the minister said he is concerned that the Egyptian authorities continue to consider Mr Halawa's case as part of a group trial.

"I have personally raised the Government's concerns about this case with my Egyptian counterpart on a number of occasions."

He said that officials in Ireland have had on-going contact with the Egyptian authorities and international partners since Mr Halawa was initially imprisoned.

The department "will continue to take all appropriate action to ensure Ibrahim's welfare, and to seek a review of his case, his release and return to his family and his studies", he added.

Meanwhile, an Egyptian court has said it will retry two detained Al-Jazeera journalists from 12 February.

Australia's Peter Greste, Canadian Mohamed Fahmy and Egyptian Baher Mohamed, all journalists with the Qatari-owned channel, were originally sentenced to up to ten years in prison for allegedly aiding the blacklisted Muslim Brotherhood.

Mr Greste, an Australian reporter, was freed a week ago.

An appeals court overturned the initial verdict and ordered a retrial.