Profits at South Korea's largest mobile phone firm have almost doubled thanks to impressive take-up of mobile internet services.

The strong results stand in contrast to many other mobile firms around the world which are struggling to persuade customers to spend money on such functions.

South Korea's market for mobiles is, like many western countries, largely saturated.

But SK telecom is managing to sell money-spinning internet services, especially picture and ring-tone downloads, much more effectively than many firms operating in western markets.

"Our earnings are better than last year because we are getting more revenue per user from internet and data services," said company spokesman Choi Young Chul.

2.5G subscriber boom

SK Telecom reported a 48% rise in profits to 900bn won ($764m) during the first six months of the year.

The firm, which commands more than half of the South Korean market, saw its subscriber base increase to 16.5 million users at the end of June compared with 16 million users at the end of March.

And the number of subscribers opting for faster, 2.5G services increased to 6.7 million compared with 5.1 million three months earlier.

Sales from mobile services rose 11% while sales from wireless internet services rose by 21%.

South Korea has one of the world's most developed mobile Internet markets and almost 40% of cellular users subscribe to some form of mobile data service.