Keith Towler took over the commissioner's role in March
The head of the independent body to help children in Wales has warned it cannot continue in its current form.
The children's commissioner in Wales Keith Towler said tough decisions had to be made about how his office worked.
He said he was not prepared for his office to seem out of control and on the back foot.
Mr Towler told the Welsh assembly's children and young people committee the organisation could not cope with current stress levels.
He said the office of the children's commissioner in Wales needed to be more strategic and there were big question marks for him over how effective it was in the way it operated now.
"We cannot maintain that level of working with the stress and sickness levels that have resulted in my office," he told the committee.
In 2001 Wales became the first part of the UK to appoint an independent children's commissioner.
Keith Towler was appointed the children's commissioner in March following the death of his predecessor Peter Clarke.
In his first annual review in the role, Keith Towler has said there was a gap between the policies which exist and their implementation.
"There remains in my mind some big question marks over the effectiveness and sustainability of some of the work that the commissioner's office has taken on," he told the committee.
He praised the achievements of his office over the past seven years saying the Clywch inquiry was a huge success.
"All of the staff are very supportive of the need for change ... some jobs will be deleted, some jobs will be amended, there will be some new jobs," he said.
"I'm not prepared for the office to be consistently on its back foot and responding to issues and seemingly out of control because that puts huge pressure on staff teams."
Mr Towler told the committee his office took calls from the public asking basic questions and they needed to be more strategic.
"We get calls like 'when does the leisure centre open?'," he said.
Mr Towler said to the assembly members he was undertaking a review of his office, but it had received a 'flat-line' budget.
"That does mean I need to take a look within the review about whether I can live within my means over the next three years," he said.
While funding was tight the commissioner said he would not want to see his budget increased if it meant raiding funds earmarked for other children's services.
"I think there needs to be a very hard look between the Welsh Assembly Government and the Westminster Government about how the children's commission is funded," he said.
"If it's about plundering money that's about direct delivery for children then that should not be happening," he said.