According to figures collected by Kaspersky Lab, the number of new pieces of Android malware tripled between the first and second quarters of 2012.
Almost half of the new malware files were multifunctional Trojans, being capable of stealing data and downloading new malicious modules from remote servers.
One quarter were SMS Trojans, which send messages to premium-rate services without the user's consent - or even knowledge.
18% were full backdoors which give attackers full control over the device, and are used to create botnets.
2% were spyware, aimed at intercepting online banking credentials and other valuable or sensitive data.
"Android's operating system is so heavily targeted because its system is flexible and easily adapted, so it's easy for cybercriminals to write malware," said Sam Bryce-Johnson, ANZ technical manager at Kaspersky Lab.
"Its success is also its downfall. As Android phones grow in popularity, they become more attractive for cyber criminals, as the malware they create is likely to reach a larger number of people than on other platforms."
Mr Bryce-Johnson predicted an increase in the quantity and effectiveness of Android malware, including the emergence of more personalised attacks.
"This is primarily about malware hunting for confidential data with which to steal money from users’ credit cards," he explained.
The company - along with other vendors such as Symantec - offers security software for Android devices.