A Finnish survey of some of the world’s most popular mobile phones found the amount of radiation they emit is well below agreed limits and largely in line with data published by manufacturers.

The annual survey by Finland’s Radiation and Nuclear Safety Authority (STUK) covered 16 new models made by top handset makers including Finland’s Nokia, Motorola of the United States and South Korea’s Samsung Electronics.

It follows the first study of 12 models done in 2003.

Mobile phones are essentially tiny radios that send and receive signals over airwaves.

All the tested models showed a specific absorption rate (SAR), which measures the amount of heat trapped by a phone user’s head, well below the 2 watts per kilogram level agreed on in Europe.

At this level, head tissue does not warm significantly and no other harmful effects have been proved scientifically, STUK said. It said the SAR levels in all the 28 models tested so far ranged from 0.45 to 1.12 watts per kilogram.

Some health advocates are concerned that mobile phone use can lead to problems ranging from headaches to tumors, but various studies on the health effects of cellphone usage have proved inconclusive.

Britain’s National Radiological Protection Board, an independent advisory group, said in January mobile phone users - especially children - should take care, although no hard evidence exists to show mobile phones damage health.

“It is important that also in the future the limits set for radiation from mobile phones and base stations are based on current and confirmed scientific proof of the effects of radiation on health,” Kari Jokela, a researcher at STUK, said in a statement.

STUK said in a statement that some of its studies have indicated that microwave radiation from mobile phones may cause small changes in how cells operate, but the findings were insufficient for concluding what effects of this radiation had on health.

STUK will start testing third-generation UMTS-standard mobile phones during 2005, focusing on the most popular models. Other phones in the current study were made by Sony Ericsson and Siemens.