Lawyers representing people with complaints before the Commission on Child Abuse have warned that the proposal to hear only sample cases may result in High Court challenges to the inquiry's work.
Mr James McGuill also confirmed that lawyers for the complainants had sought a meeting with the Attorney General to discuss the proposed review of the commission's work.
They want specific information on how the Government calculated that the commission could take 10 years to conclude its work.
This request follows a meeting on Thursday night of a group of lawyers who represent the majority of those who have made complaints to the commission's investigation committee.
"We're seeking a meeting with the Attorney General," Mr McGuill said. "We're seeking to be informed how the Government arrived at its conclusion that the inquiry could take 10 years. We'd like to look at their figures to see how they concluded this." He said solicitors for the complainants had not been asked to provide information for the review, and warned that the proposal being considered by the Government to hear only sample cases could be open to High Court challenges.
"There may very well be legal challenges. All applicants have a legitimate expectation of getting a full hearing. If the Government is going to mess around with that, it is going to lead to all sorts of legal problems, including the possibility of High Court challenges."
Meanwhile, the commission has warned complainants not to commit any further resources to their cases before the investigation committee.
In a letter to solicitors representing the 1,700 complainants, commission staff reiterated that the investigation committee had suspended its work. It says it regrets that it has "felt constrained to take this decision.
"In the circumstances, your clients should not commit any further resources to preparation for evidence-gathering or hearing until the investigation committee has had an opportunity to consider the position in the light of the conclusions of the Government's review."
Senior officials from the Department of Education are to meet with representatives of victims and survivors groups early next week to discuss the ongoing review. Most of the groups have voiced outright objection to the sample cases method.
Under this proposal, the inquiry would not investigate each allegation but would take a statistical sample in order to speed up the work of the inquiry.