His comments came as it emerged the archbishop himself, priests, complainants and others featured in the report have received its contents and are in the process of drafting replies ahead of its imminent publication.
Dr Diarmuid Martin made his comments while also warning there had been a dramatic rift between the Church and young people in Ireland that needed to be addressed.
Delivering his Holy Thursday Homily at Dublin’s Pro-Cathedral, the head of the Catholic Church in the south said his diocese was coping with difficult times.
“The Archdiocese of Dublin is facing challenges of a kind that it has not experienced for many years. The report of the Commission on Child Sexual Abuse will shock us all,” he told Mass attendees.
The inquiry is scheduled to be fully written in May. It will then be handed to the Cabinet, which will decide on its publication.
The inquiry has already been granted two extensions, both of which were missed.
Commission member Ita Mangan yesterday told the Irish Examiner the report was “largely written”.
“It is almost finished and will be ready in May. Then we send it to the Government,” she said.
Allegations investigated in the report have already been sent to priests and bishops concerned.
Those featured in the report are currently drafting replies to the Commission which are expected to be included in the final copy.
Complainants and gardaí have also been sent sections relevant to them.
Archbishop Martin has seen the report and is also drafting his own response.
“It is likely that thousands of children or young people across Ireland were abused by priests in the period under investigation and the horror of that abuse was not recognised for what it is,” Archbishop Martin told his parish yesterday.
The commission has examined more than 75,000 documents from the Dublin diocese.
Separately, it has also received thousands of documents from the Health Service Executive and gardaí.
At least 400 victims of abuse have been identified.
Archbishop Martin warned that the Dublin diocese was “facing challenges of a kind that it has not experienced in many years”.
In the diocese, there are now 10 times more priests aged over 70 than those aged under 40.
It is estimated that in a few years, the diocese will have just more than 200 priests to minister to some 200 parishes.
“Inevitably the structures of priestly ministry will have to change, while at the same time the diocese of Dublin needs new priests.”
The archbishop also raised concern about a widening rift between the Church and young people and stressed that parishes needed to offer more facilities while reaching out to Ireland’s young.