In a tweet, the company attributed the problem to an "authentication system outage" that lasted for approximately 45 minutes starting at 7.32am Eastern time in the US (11.32pm AEDT).

"We apologise for the inconvenience and thank you for your patience and continued support," Google said on its website. "Please rest assured that system reliability is a top priority at Google, and we are making continuous improvements to make our systems better."

Outages are not uncommon for any website or provider, with companies including Google as well as Apple, Amazon, Microsoft and others routinely experiencing them due to temporary server errors often caused by human error. But Monday's outage is notable for its pervasiveness across the Alphabet portfolio.

The company's search product was functioning correctly, and third-party ads – Google's main revenue driver – remained visible in results, suggesting advertising was unaffected.

The website DownDetector, which collates user-reported errors on websites, mobile networks and other platforms, was showing tens of thousands of complaints around 7am in New York, extending to Google's office tools such as Drive and Meet, Google Maps, and Google's smart home products such as Nest.

The popular mobile game Pokemon Go was also impacted, reports on DownDetector implied, most likely caused by Google accounts being necessary to login to the game.

Bloomberg, with AP