Israeli researchers say they have found that the regular use of mobile phones increases the risk of developing tumours.

The researchers from the Chaim Sheba Medical Centre in Israel examined data from 402 benign and 58 malignant cases of parotid gland tumour which were recorded in Israel between 2001 and 2003; the patients were aged 18 years or older.

The research was part of a World Health Organisation project and was led by Dr. Siegal Sadetzki, a cancer and radiation expert.

Previous studies sponsored by the mobile phone industry have found no association between tumours and the use of mobile phone.

However such studies considered data for less than ten years of exposure to the cell phone radiation and tumours are likely to develop ten years after exposure.

The study revealed that people who used mobile phone for more than 22 hours per month increased their risk for a parotid gland tumour by 50 percent.

The risk was apparently even higher if users used the same ear, did not use hands-free devices or lived in rural areas.

The study supports other evidence that the mobile phone increases the risk for developing tumours including brain tumours in heavy users.

The study is published in the American Journal of Epidemiology.