Maggie Atkinson said a change to the law would encourage professionals, such as social workers and doctors as well as school staff, to share their concerns with others.
There is already statutory guidance compelling professionals who come in to contact with children to report child abuse.
However, failure to do so is not a crime in England, Scotland and Wales. In Northern Ireland, it is against the law to fail to disclose an arrestable offence to police.
However, ministers said there was no evidence that such a move would make children any safer.
Ms Atkinson called for a series of pilots to be launched to trial the idea.
She said: “We strongly believe pilots should be carried out to provide this evidence and children’s views must also be considered before a firm decision is made because we think there must be sound justification for not proceeding with a requirement on professionals to report abuse.
“Any changes to the law would need to be accompanied by better training so that staff are far more proficient at identifying and supporting child victims of abuse.”
She said that children needed to feel they were listened to, and to be kept informed of how any reports of abuse were going to be dealt with.
Keir Starmer, the ex-director of public prosecutions for England and Wales, made a similar call recently, when he said that teachers and other professionals who did not report suspicions of child abuse should be prosecuted and face jail sentences if convicted.
The calls come following a number of cases of child abuse coming to court featuring a failure by professionals to report abuse. The Department for Education said mandatory reporting was “not the answer”.
A spokesman said: “Guidance is already crystal clear that professionals should refer immediately to social care when they are concerned about a child.
“Other countries have tried mandatory reporting and there is no evidence to show that it is a better system for protecting children. In fact there is evidence to show it can make children less safe.”
Teachers’ leaders said procedures relating to the safeguarding of children were complex and needed appropriate school policies to be put in place.
Bodies representing doctors also urged caution. The British Medical Association said it was against mandatory reporting.
A spokeswoman said in the vast majority of cases, doctors already reported their suspicions and there were cases when such action might not be in the best interests of the child.
Dr Tony Calland, chairman of the group’s Medical Ethics Committee, said: “A decision not to report immediately is not a decision to do nothing. It may involve looking at other ways of supporting a child or managing risks.”