Halawa has been jailed, awaiting trial, since 2013 after he was detained at a protest in Cairo's Ramses Square.
Ibrahim Halawa has been awaiting trial since August 2013, along with 493 other people.
He was detained in one of a series of sweeping arrests made at a protest in Cairo in the days following what has come to be known as the Raba'a crackdown.
Halawa and his sisters reportedly joined the protests in Ramses Square in outrage at the death of at least 817 people in Raba'a square three days earlier.
His case has yet to be tried in an Egyptian court, as the authorities have struggled to find a court room big enough to hold 494 people.
The case also includes at least nine people, including Halawa, who were minors at the time of their arrest.
But Nosayba Halawa says that, while she is grateful for the efforts of the Irish government, she feels requesting a fair trial is asking for the impossible in Egypt.
"I want the Irish government to ask for his release,” she told RFI. “I don't want a fair trial for my brother. There is no fair court or justice in Egypt. If he was anywhere else in the world, he wouldn't spend a minute in prison."
She also says that requesting a fair trial could also have unintended consequences:
"They're asking for a fair trial and I want them to ask for immediate release for my brother. I don't want them to wait until my brother gets the death penalty and we have to come and say "Please, can we wait for that to become a trial so that maybe he gets 10 or 15 years.""
The mass trial of 494 people, including Halawa, is scheduled for early February.
However there is no guarantee that the hearing will take place, as the Egyptian authorities are yet to find or build a venue big enough for the trial.