Documents released under Freedom of Information legislation show Tusla had raised concerns with the Department of Children.
The agency fears that the introduction of mandatory reporting from January 2018 will place severe pressure on its child protection services and reverse the progress it has made in dealing with social work.
According to documents given to RTÉ’s This Week programme, the estimated increase in referrals could be anywhere between 22,000 and 65,000.
Chair of the national review panel on serious incidences including deaths of children in care, Dr Helen Buckley, said Tusla was in a “pretty fragile” position.
Past criticisms of the agency had not been about unreported cases or the process of reporting incidences but about their failure to work acceptably.
“You can see from their strategy that they are trying to address those problems, but it is going to be very challenging,” she said.
There was also a capacity problem because there were not enough qualified social workers to fill posts already approved.
Dr Buckley believed that Tusla would have to “mechanise” its intake system and set up call centres to deal with mandatory reporting.
“They are going to have to dedicate resources to that kind of service provision rather than improve the quality of the services they are already operating.”
The Ombudsman for Children, Dr Niall Muldoon, has called for greater support to be given to the agency to implement mandatory reporting, so that new referrals could be dealt with appropriately.
Tusla reckons that referrals of child abuse will more than double because of mandatory reporting and such a development is a reason not to introduce it.
“I would have the opinion that such estimates make it even more urgent that we bring this law into force, and do everything in our power to allow the voices of these young people to be heard so that appropriate help can be provided,” said Dr Muldoon.