The "Gone Google" campaign, which includes the UK, France, Canada, Australia and Japan, is aimed at luring businesses away from traditional office software supplied by Microsoft and IBM.

The US campaign, which started in August, features advertisements in major online and print publications as well as billboards at airports and train stations in various cities, according to reports.

Google will attempt to persuade more businesses to switch to the cloud-based software-as-a-service model.

The internet firm claims to have over two million business users of Google Apps, but has not disclosed how many are paying customers.

Larger businesses pay £50 a year for Google Apps, but the service is free to businesses with fewer than 50 employees.

The firm claims there are 20 million active users of Google Apps, but that number includes students who use the free version Google provides to universities.

The expansion of Google's advertising campaign, which is due to run for the rest of the year, comes as rivals IBM and Microsoft step up competition in the cloud with online versions of their software.

This article first appeared in Computer Weekly.