Google has expanded its web-based security application which allows administrators to set policies that limit user access to sites and monitor browsing habits.

Google Web Security for Enterprises, which also provides malware protection, is based on software acquired by Google when it purchased Postini last year for $625m.

Previously, using Google Web Security for Enterprises outside a company network had required users to manually log-in through a virtual private network.

The company has now expanded the tool to allow it to operate on computers outside the network. This will allow administrators to enforce web browsing policies on roaming users and employees working off-site.

"All off-network web traffic is automatically directed to a scanning infrastructure to enforce policies and protect computers, requiring no action on the part of individuals," said Google product marketing manager Tim Johnson.

"It is easy to deploy and users cannot tamper with it, ensuring that security and appropriate usage policies are always in place."