But what is the impact on a child of carrying such a message, and of being in a violent protest?

Child and adolescent psychologist Clare Rowe said it was ''alarming and inappropriate'' to see children involved in demonstrations with violent messages behind them. They could grow up believing that reacting ''impulsively with violence and intolerance'' was the way to respond to people who disagreed with them.

''These protests and many others like them revolve around issues such as religion and union workplace action - concepts that are vastly above that of the developmental understanding of a young child,'' Dr Rowe said.

''Without understanding the deeper issues at the core of the matter, the child simply witnesses the anger and hatred in which the adult role figures around him react. By placing a child in the centre of such a movement we are effectively telling him or her that it is OK to react in such an unacceptable manner.

''Surely this is an attitude which will only disservice them throughout their lives, both in school and the workplace.''

Kirsty O'Callaghan, a parenting and relationship expert at Unity-Qld, said older children brought along to protests could also be mirroring their parents' beliefs rather than expressing their own.

''They are going through the role modelling stage [between the ages of seven and 14] so they are watching the adults around them … they are looking for the approval of their parents … Is that reason enough to have them at a protest?''

Azza Brown, an educational and developmental psychologist and a member of the Australian Psychological Society, said while some parents wanted to involve their children in issues that they felt strongly about, children were more likely to absorb the feelings of the protest, rather than the issue about which their parents were trying to teach them.

Ms O'Callaghan said it was important for parents to sit down and explain why they were going to demonstrations.