Australia's central bank and postal service, and several commercial lenders, were left grappling with internet outages on Thursday (June 17).
The disruption impacted customer accounts and financial transactions.
Although some services were restored late in the day.
Virgin Australia was also hit, but said the situation was now resolved.
The country's No. 2 airline said it used Akamai, a third-party system, for IT network authentication.
Representatives for Akamai did not immediately respond to requests for comment.
Websites in Australia, including those belonging to the central bank, the Commonwealth Bank of Australia and others had also started to come back online late afternoon.
The Reserve Bank of Australia cancelled an operation to buy government bonds because of the technical difficulties.
Websites of American Airlines, Southwest Airlines, United Airlines and Delta also experienced disruptions on Thursday.
It was not immediately clear if the outages in Australia and the United States were linked.
The problems come a little over a week after thousands of government, news and social media websites around the world were hit by a widespread technical issue linked to U.S.-based cloud company Fastly.