Security experts have warned that new smartphones, such as the Apple iPhone, and those using Google’s Android software could be at an increased risk of attack from malicious software.

Smartphones, which allow software applications to be downloaded and installed, could “open the door for hackers” to release malicious software that attempts to gain access to users' passwords and online details, said Simon Church of iDefence and Richard Hales UK of F-Secure.

Mr Hales said that malware on PCs originated from "hobbyists and people with too much curiosity, but now more than 95 per cent of malware is created for commercial gain. We fear the same development will follow in mobile field”.

Although mobile phone viruses have been around since 2004, they have not become as widespread as those found in PCs. F-Secure predicts that around 400 types of infection have been discovered since then. These have been reliant on users opening infected picture messages or accepting Bluetooth transfers that contain malicious software.

However, Mr Church said that these attacks were set to evolve as a result of advanced mobile technology and the fact that people were using their handsets for more than just calls.

"People now use their handsets to send emails containing personal information and some even use them for online banking", he said.

"The iPhone and the Google Android phone let people develop and download third-party applications, such as games and payment services. The bad guys know this and they too are developing software."

He said phone viruses could be used to download keylogging tools that monitor the buttons people press, and could therefore be used to steal passwords used in online banking.

But a spokesperson for security firm Kaspersky advised people not to panic, claiming that such an attack is currently some way off.

David Emm, senior technology consultant at the security company, said: "We are beginning to see a head of steam building up around these types of mobiles. However it's going to take a little while for lots of people to get these phones, and it's proven that criminals only go after technology that can really make them money so we not at this point yet."

He warned, however, that users of modified iPhones were more at risk. "The current state of the iPhone means that people are limited to the applications they can download. Those unlocking it won’t have this protection” he said.

Google and Apple had not yet commented at the time of publication.