Google has developed an in-house anti-virus service to remove malware on its marketplace.
The Bouncer service emulates the operating of application on Google's cloud and searches for anomalies that may be indicative of malware.
"We also analyse new developer accounts to help prevent malicious and repeat-offending developers from coming back," Android engineering vice president Hiroshi Lockheimer said.
Lockheimer credited Bouncer with lowering the number of "potentially" malicious downloads in the Android Market by 40 per cent, between the first and second half of last year.
Google did not say why it delayed the creation of the service.
Lockheimer admitted the drop was contrary to findings from other security firms.
Juniper Networks found malicious Android samples spiked 472 per cent since July, while Lookout Mobile Security said malware stole more than $US1 million ($A929,000) from Android users last year. It claimed the annual malware-encounter rate increased to four per cent.