The trouble for Google started when security outfit zvelo demonstrated how a brute force attack on a rooted mobile phone could expose a user's PIN. This was followed by a more serious discovery from The Smartphone Champ which revealed that an option to clear data and reset payment options on the phone makes it easy for anyone who finds or steals an Android phone to take over the wallet function.

In a blog post over the weekend, Google Wallet VP Osama Bedier strongly discouraged Wallet users from attempting to gain system-level 'root' access to their phones, as the application is not supported on rooted phones. "In most cases, rooting your phone will cause your Google Wallet data to be automatically wiped from the device," he says.

To address the second issue, Bedier says the firm has taken immediate action to temporarily disable provisioning of pre-paid cards. "We took this step as a precaution until we issue a permanent fix soon," he says.

Bedier accepts that Google is still learning from its experiences in the mobile payments world, but maintains that the phone continues to offer more security than credit cards and leather wallets.

"Mobile payments are going to become more common in the coming years, and we will learn much more as we continue to develop Google Wallet," he says. "In the meantime, you can be confident that the digital wallet you carry provides defences that plastic and leather simply don't."

Update Google issued the following update at 8.30pm on 14 February: "Yesterday afternoon, we restored the ability to issue new prepaid cards to the Wallet. In addition, we issued a fix that prevents an existing prepaid card from being re-provisioned to another user. While we're not aware of any abuse of prepaid cards or the Wallet PIN resulting from these recent reports, we took this step as a precaution to ensure the security of our Wallet customers."