Archbishop Diarmuid Martin has said that he was obliged to con-celebrate mass with two bishops who were involved in the cover up of clerical abuse.
However Archbishop Martin has acknowledged that the con-celebration with bishops Dermot O'Mahony and Eamonn Walsh had caused unnecessary hurt to Marie Collins and other abuse victims.
The mass last Sunday marked the feast of the archdiocese's patron saint and founder, St Laurence O'Toole. The archbishop added that it was custom for the senior clergy who held official positions to take part in the mass.
Dr O'Mahoney, who is now retired and Dr Walsh assisted at the Mass. Cardinal Sean O'Malley, Archbishop of Boston, was the fourth celebrant.
After the mass, Ms Collins a victim of clerical child abuse expressed hurt and anger at the involvement of Cardinal O'Malley and Dr Martin.
Ms Collins said it was a “poor start” for Cardinal O'Malley's investigation.
In response to Ms Collins' comments, Dr Martin said: "They (Dr O'Mahony and Dr Walsh) belonged to the Metropolitan Chapter. I could do nothing about it.
After issuing an apology to Ms Collins and other abuse victims he said: "I am aware of the hurt that has been caused to people."