Researchers are recruiting 108 children for tests to start next year.

The study will expose children to a mobile phone, or the equivalent electromagnetic energy, and look for changes in the electrical activity in the brain during a normal night's sleep.

Illawarra Health and Medical Research Institute psychologist Rodney Croft, who is leading the research, said phones had become ubiquitous but evidence of their harmlessness to children was lacking.

"There's a pretty strong consensus that there's not a problem in adults, but people have only started doing research on children in the last five years and very little has come out of it," he said.

"We've got no reason to believe that there'll be a greater effect in children than in adults.

"But we just don't understand well enough the maturational phases that children go through, so it's possible there's greater sensitivity."

The Wollongong study will be part of a wider research project being administered by Monash University in Melbourne.

The federal government recently announced funding of $2.5 million for the broader project, with $700,000 devoted to the Wollongong arm of research.

The funding will allow the institute to employ two post-doctoral researchers for five years.

Researchers want to recruit 36 children in each of three age groups: 10-12, 13-15 and 16-18.

It is the second significant research grant in as many years to Professor Croft, who in August 2012 became the first University of Wollongong researcher to lead a Centre for Research Excellence examining possible health concerns associated with mobile phone use in adults.

That particular research, which is a five-year project, is ongoing.