Announcing the restoration of services, the company wrote: "The problem with Gmail should be resolved. We apologise for the inconvenience and thank you for your patience and continued support.
"Please rest assured that system reliability is a top priority at Google, and we are making continuous improvements to make our systems better. If you are still experiencing an issue, please contact us via the Google Help Centre.
"We will conduct an internal investigation of this issue and make appropriate improvements to our systems to prevent or minimise future recurrence. We will provide a more detailed analysis of this incident to the affected customers once we have completed our internal investigation."
Despite the issue taking nearly a full day to resolve, Google did not classify it as a service outage, but rather as a service disruption.