According to Dawn Sukyi, of China's NetQin, the botnet viruses are being disguised within some of the 'hot' online topics on the internet.

"For now, it's the World Cup frenzy that's going on, but it has also been seen as the 'most popular blind date TV show', amongst other hot topics", she said in a security blog posting.

NetQin says that its research team has found that the botnets do one of two things; send messages to all the contacts of the mobile's address book directly, or send messages to random phone numbers by connecting to a server.

"The viruses will delete the sent messages from the user's [messaging] outbox and SMS log. All messages contain URLs linked to malicious sites that users won't be able to see until after they've fallen into the virus trap", Sukyi explained.

According to the Beijing-based NetQin researcher, the botnets are targeting Symbian S60 3rd and 5th generation operating systems.

The new botnet viruses are said to have started causing trouble on mobile devices but the firm's research team have managed to detect them - and are working with operators to try and put a stop to them.