Next time you're chatting on your mobile phone, it may be worth stopping to think about the health risks.
Although the link between mobile phone use and cancer remains unclear, new research suggests that a risk is there, however the severity continues to be debated.
A 10-year study on the health effects of mobile phone use found a 24 percent increased risk of the most common type of brain tumor, glioma, on the side of the head a handset was help for regular phone users.
The study, which was done by Interphone, was carried out across 13 countries including Australia and focused on people aged 30 to 59.
Researchers found that using a mobile phone for more than half an hour a day could increase users' risk of developing brain cancer by as much as 40 percent.
But American lobby group Environmental Health Trust told the UK's Daily Telegraph that the real risk could be 25 percent greater than the Interphone study suggests.
Electronic engineer Lloyd Morgan from the group said a "brain tumor pandemic" will be faced in the future due to the 4 billion phone users' worldwide that are using their mobile phone for extended periods of time.
"What we have discovered indicates there is going to be one hell of a brain tumor pandemic unless people are warned and encouraged to change current cell phone use behaviors," Morgan said.
"People should hear the message clearly that cell phones should be kept away from one's head and body at all times."
Interphone researchers have admitted that their findings were not conclusive and could have been affected by statistical error or bias.
A spokesman from the Australian Radiation Protection and Nuclear Safety Agency says there have been very few studies done on the link between mobile phone radiation and cancer and usually direct information was not available.
"The results of these studies are difficult to interpret because exposure levels were either not measured or impossible to determine from the data provided," the spokesman said.
"In general, however, this type of study will be useful in identifying possible links between mobile telephone use and cancer risk," he said.
"The Australian Radiation Protection and Nuclear Safety Agency continues to closely monitor the research being conducted in this area."
The spokesman also said it was important to note that such cancers existed before the introduction of mobile telephones.
"It is simply not possible to identify the cause of any single case of cancer," he said,
"Long-term studies to investigate whether mobile telephone users have a greater incidence of, say, brain cancer than the general population has not been completed."