The agency that provides services to help vulnerable children is struggling to recruit social workers to deal with more than 5,400 unallocated cases, 801 of which are considered high priority.
Children's Minister Katherine Zappone said that there aren't enough social work graduates and that Tusla expects to be around 100 short of its hiring target this year.
Ms Zappone told the Oireachtas Children Committee that funding for the agency has been boosted by €37m this year to €713m.
She said while this funding will help alleviate the backlog in cases that don't have social workers assigned to them, recruiting new staff has been "challenging".
Ms Zappone said Tusla is in the second year of a three-year plan to tackle the problem. The plan stated that 1,627 whole time equivalent social workers were needed. She said Tusla's current target is to recruit 53 full-time equivalent social workers this year bringing the total to 1,520. The minister conceded that this was around 100 short of the number the agency had originally hoped to hire.
"It reflects, I think, the restraint in relation to labour supply," Ms Zappone said. She told TDs how third-level institutions produce just 250 social work graduates a year and said "it's a very competitive labour market".
She insisted funding is in place to achieve the recruitment levels necessary and that other staff are being hired to allow social workers to focus on their care work with children and their families. Tusla is also attempting to recruit social workers abroad.
Ms Zappone also said her officials will be meeting the Higher Education Authority to examine how the number of graduates can be increased.
The number of unallocated cases is down to 5,413 from almost 10,000 when Tusla was first established in 2014.
A total of 801 of these are classified as high priority.
Ms Zappone said the last two months of 2016 saw an increase of more than 1,100 unallocated cases and put this down to the recruitment challenges.
Sinn Féin TD Donnchadh Ó Laoghaire raised concerns about the number of unallocated cases that are classed as high priority.
He suggested any "quick fix" could focus on ensuring there are support staff to allow social workers to concentrate on their cases.