In a significant research supported by the World Health Organization, evidence found excessive mobile phone users may be exposed to increased brain cancer risk, but the findings were not conclusive.

While the study found no increased risk of cancer associated with mobile phone use, but in some cases, users may face unexplained suggestions of greater risk for developing brain tumours.

The major research that involved 13 countries, with more than 5,000 participants and 21 researchers, also included two Australian scientists.

The potential for increased risk of certain cancers associated with mobile phone usage needs to be studied more through future research, says Dr Bruce Armstrong of the University of Sydney.

Though the study suggested potential cancer risk from excessive mobile phone use, Dr Armstrong says it does not strongly state an issue is evident with respect to brain cancers and mobile phone use.

He says, I don't think we can say there was an increased risk. The study provides some evidence that there might be an increased risk.

Dr Armstrong, however said from a public health view, there was no proof brain cancers had increased since mobile phone use became widespread.