The 2007-2008 Report on Child Health findings add more weight to calls for a population health study into the impacts of the Hunter's coalmining and power-generation industries.

The study results were compiled from a telephone survey of 600 parents and carers of children under 15 in the Hunter New England Health Area.

The results show 25.6 per cent of 2- to 8-year-olds and 39.8 per cent of 9- to 15-year-olds living in the Hunter New England Health area have been diagnosed with asthma.

The figures are the highest of any of the state's eight area health services.

The region also has the second-highest percentage of 2- to 8-year-olds and the highest percentage of 9- to 15-year-olds living with asthma.

The release of the results coincided with yesterday's meeting of an expert panel appointed by the Department of Health to inquire into the adequacy of the Hunter's air pollution monitoring.

The panel is also using health data to examine the region's incidence of cardiac and respiratory illness, which may lead to further studies.

Singleton GP Tuan Au, who has been calling for the Government to investigate the high incidence of asthma in the Upper Hunter, said the results were not surprising.

"The next step is what are we going to do with these statistics?" he said.

"We need more education for parents not to smoke in front of their kids but most importantly we need to find out why [asthma incidence] is so high."

Public health physician David Durrheim said the results could not be localised to a specific local government area.

He said multiple environmental factors in rural areas contribute to the exacerbation of asthma conditions.

These include agriculture, drought, bushfires, mining and industry and seasonal pollens.

"All of these factors are present in the Hunter New England Health Area and could contribute to report findings," he said.