One in five children suffer chronic pain and it mostly affects adolescent females, a leading expert in the field says.

Pain specialist and anaesthetist at Sydney Children's Hospital Emily Yeoh said unlike adults, there were no set guidelines for weaning children off medication for persistent pain and after surgery.

"A lot of pediatric pain we ascribe to adult principles. Depending on the operation, it usually takes between one to two weeks (to taper off) if they are on low-acting opioids,'' Dr Yeoh said.

''They're likely to be on other medications often for up to six weeks post-operatively. For instance, for scoliosis repair - or back repair - it's a very painful operation so most children are on medication for six weeks but we would expect them not to be using the long-acting opioids after one to two weeks.

"An adult probably wouldn't cope with that type of operation. These kids are up and walking around the ward by day three. Adults are a lot slower to progress.''

She told the Australian and New Zealand College of Anaesthetists' annual conference in Sydney that children were also much more accepting of non-pharmacological therapy and management of their pain than adults and addiction was extremely rare.

Children embraced pain-coping mechanisms such as the use of stress balls and deep breathing techniques, whereas adults generally expected drugs to manage pain.

"Children don't like taking medication and they're very happy when they come off it,'' Dr Yeoh said.

Patients could be physically dependent on medication and experience withdrawal but that was usually for children who needed strong drugs to tolerate intensive care treatment.

Only a few patients presenting in chronic pain clinics had addiction problems and those who did had usually started using opioids before. That was not the norm.

Stressful life events could cause chronic pain such as inflammatory bowel disease, stomach and joint pain.

A further complication was that long-acting drugs catered only to adults.

"There's nothing about syrup formulations for children yet but it's easier for pharmacists to dispense a smaller quantity,'' Dr Yeoh said.

The absence of long-acting opioid syrups was a problem for some palliative care and cancer patients.

"They need to be able to swallow tablets.''

Short-acting opioids available for children are oxycodone and morphine syrups. Though they have the potential for addiction, Dr Yeoh was not concerned about childhood addiction.

The biggest problem managing childhood pain was lack of recognition and resources, she said.

"Twenty per cent of children could have chronic pain - that's a large number and there are only three pediatric pain clinics in NSW: Sydney Children's Hospital, Westmead and John Hunter children's hospitals.

"More resources and funding for chronic and acute pain would be great.''