An Australian judge, brought in to hear the case, is to issue his decision on the group's appeal for a permanent stay.
The Nauru 19 had protested outside parliament in June of 2015 - an event the government continues to call a riot.
They are facing various charges including rioting, disturbing the legislature and entering a restricted area.
But in June the Nauru 19 sought a permanent stay on the charges, contending the trial process had dragged on too long and the Nauru Justice Department had not met a court directed order to pay some of the expenses of the group's Australian lawyers.
Justice Andrew Muecke had said in his decision the law had to be applied fairly, and for this to happen the Nauru 19 needed the Australian lawyers, because local legal representation was not available.
The lawyers have been working pro bono since 2016, with the Nauru 19 covering their basic costs, but with the government limiting this group's options for employment on the island, they could no longer do this.
Justice Muecke is set to announce his decision on the permanent stay application on Thursday.