Government services minister Stuart Robert has quickly walked back his claim that the online services portal myGov suffered a “significant distributed-denial-of-service (DDoS) attack”.

Robert initially blamed problems with the site on a DDoS attack that left thousands of Australians locked out while attempting to access welfare services on Monday.

But less than two hours after first making the claim, Robert backtracked, saying there was no attack and the site was simply overloaded.

Robert said the number of users hitting myGov this morning was almost double the 55,000 the site is designed to concurrently handle.

He also told Parliament during question time the systems had experienced "multiple and sustained DDoSs over the past few weeks".

“This, combined with all of the data - [from] 95,000 users - gave rise to a very strained performance because of the high number of usage and that caused the outage," he said.

“The DDoS alarms show no evidence of a specific attack today. That doesn’t mean there is no need for heightened cyber security.”

The Australian Cyber Security Centre also confirmed the myGov outage was not the result of "malicious cyber activity", though said the government was investigating the cause.

"The ACSC is engaging with Services Australia on this reported incident and will continue to provide assistance," a spokesperson said.

"At this stage, the ACSC has no evidence to suggest this outage was caused by malicious cyber activity."

The outage came after the government boosted the fortnightly welfare payment for jobseekers, and announced new measures to allow individuals to apply to access part of their superannuation.

All states and territories will begin shutting down “non-essential services” from midday today to tackle the spread of COVID-19.

Services Australia has already increased the number of concurrent users the site can support from 6000 to 55,000 in response to the coronavirus pandemic.

“We’ve been preparing for a large influx of Australians who haven’t yet used Centrelink service before,” he said.

“Over the weekend we took our number of users on myGov from an average 6,000 concurrent users to what is now 55,000 concurrent users.

“We’ve put a tenfold increase on our digital channels over the weekend in preparation."

Services Australia is now looking at ways to increase myGov’s concurrent user load “even higher”.