Amazon.com said on Monday that a cloud computing unit at its data centre in northern Virginia had largely contained fallout from a widespread internet outage that caused global turmoil among thousands of sites, including some of the web's most popular apps like Snapchat and Reddit.

Amazon said it had addressed the underlying issue and was close to a resolution, but some users were still complaining of lingering difficulties using services such as digital wallet Venmo and video calling site Zoom.

The disruption knocked workers from London to Tokyo offline and halted others from conducting normal everyday tasks like paying hairdressers or changing their airline tickets.

It was the largest internet disruption since last year's CrowdStrike malfunction hobbled technology systems in hospitals, banks and airports, highlighting the vulnerability of the world's interconnected technologies.

It was at least the third time in five years that AWS's northern Virginia cluster, known as US-EAST-1, contributed to a major internet meltdown.

The problems stemmed from what is known as the Domain Name System, or DNS, which prevented applications from finding the correct address for AWS's DynamoDB API, a cloud database relied upon to store user information and other critical data.

After hours of disruptions, many applications were gradually coming back online in the afternoon in the US. But AWS acknowledged that elevated errors were still affecting several services.

While some apps like Reddit and Roblox had largely stabilised, according to outage tracking website Downdetector, others, including Snapchat and Duolingo , were showing a resurgence in issues seen earlier in the day.

AWS provides computing power, data storage and other digital services to companies, governments and individuals and is the world's largest cloud provider, followed by Microsoft's Azure and Alphabet's Google Cloud.

Disruptions to its servers can cause outages across websites and platforms - ranging from food delivery apps to gaming platforms and airline systems - that rely on its cloud infrastructure.

The problem highlights how interconnected everyday digital services have become and their reliance on a small number of global cloud providers, with one glitch wreaking havoc on business and day-to-day life, experts and academics said.

"This outage once again highlights the dependency we have on relatively fragile infrastructures," said Jake Moore, global cybersecurity advisor at European cybersecurity firm ESET.

In Britain, Lloyd Bank, Bank of Scotland and telecom service providers Vodafone and BT were all hit, according to Downdetector's UK website, as was UK tax, payments and customs authority HMRC's website.

"The main reason for this issue is that all these big companies have relied on just one service," said Nishanth Sastry, director of research at the University of Surrey's Department of Computer Science.

Ookla, which owns Downdetector, said over 4 million users reported issues due to the incident, and at least a thousand companies were affected.

Wall Street was largely unfazed, sending Amazon shares 1.6% higher to US$216.48. (Reuters)