Some children are overlooked because they are conscientious students and it is difficult to know they are constantly worrying, says Ron Rapee, Professor of Psychology at Macquarie University.

Common concerns include a fear of making mistakes, always being on time, family finances, health, crime, friendships or being laughed at.

The children might always expect the worst, suffer stomach pain and headaches and have trouble sleeping, says Prof Rapee, who is director of the Centre for Emotional Health at the university.

"But the strongest indicator of anxiety is avoidance. Most anxious children have a range of things that they just refuse to do.

"The central problem is they fear people will think badly of them," says Prof Rapee, a who is running a workshop on childhood anxiety at a College of Clinical Psychologists Conference in Melbourne.

His aim is to teach colleagues how to use the university's Cool Kids program to help children aged seven to 17, and their families.

Most anxious children can be helped, he says.

Parents can start with basic common sense procedures like talking to the child about the evidence for their worries and gradually encouraging the child to do the things they are afraid of doing, he says.

If necessary, parents can ask a GP for a referral to a clinical psychologist or use Cool Kids resources to coach their own children. Children in Sydney can attend sessions at the centre.

"Anxious children often exaggerate the danger or catastrophise the situation. We teach them to consider if there is evidence for what they are worrying about," says Prof Rapee.

The program gets children to face their fears in a systematic way.

"They gradually confront things they are fearful of."

However, it's important for parents not to over-react to every child's worries.

"Anxiety is a natural emotion. All children will go through periods of being anxious. What we are looking for is where the anxiety goes on for long periods and where it interferes with a child's life."