Google Inc's email service, Gmail, suffered its second technical problem in a month on Thursday as users reported difficulty accessing their contacts.

The disruption lasted 2 and a half hours to resolve and earlier this month, a majority of its email users were unable to access the service for more than an hour after routers got overloaded during a routine server upgrade.

A problem with Google Contacts caused many Gmail users to experience slowness and degraded service for about an hour today, Google said in a statement.

Mail was back to full speed for everyone around 8am Pacific and the issue affecting Contacts was resolved shortly after. We're sorry for the inconvenience. As usual, we'll provide an incident report on the Apps Status Dashboard, where we also gave ongoing status updates as this issue progressed.

The persisting outages have raised concerns as more and more businesses consider adopting cloud computing technologies offered by Google as well as and, which help deliver data and services over the Internet.