Google Android users need to be wary of rogue apps that try and steal personal data from their handset, says Bullguard.

The internet security firm issued the warning as it was revealed that more than 50 malicious apps had been discovered in the Android Market.

"Spyware doesn't behave like a virus on a desktop computer. Spyware is designed not to disturb or destroy anything as its mission is to secretly obtain and transmit information without being detected. The information is then traded on a 'black stock exchange' where the going rate for credit card information is good, and subject to the same rules of supply and demand as on the legitimate markets", says Philip Dall, mobile security expert with internet security company BullGuard.

"We've become accustomed to having an antivirus program on our computer, which also protects against spyware. But when it comes to mobile phones, there is virtually no awareness about the very same risks and few have a security program for their Android phone."

Philip Dall recommends that Android users consider two basic security measures to stay safe:

Dall advised Android users to "think twice before you download applications by finding out who uploaded it, check which rights and actions the app wishes to make use of, and consider whether this sounds right or not". He also urged Android smartphone owners to consider installing security software on their handset. There are many mobile security products available including offerings from BullGuard, AVG and Trend Micro.

Gartner recently revealed Google Android is now the second largest mobile phone operating system, with 67.2 million handsets sold last year.

See also: Bullguard offers 5,000 free licences for mobile phone antivirus software