The telco said it's now investigating the issue, which is impacting "a number of enterprise customers nationally".
Australian banks and retailers were getting back online on Thursday after a nationwide telecoms outage knocked out electronic payment systems and cash machines for several hours.
Caltex service stations, Coles and Woolworths stores, Big W and liquor retailers BWS and Dan Murphy's weren't spared from the outage.
Commonwealth's CommBank and NetBank mobile apps are said to be still in operation, but CBA ATMs, EFTPOS terminals, "some in branch services" and the CommSec website are affected.
Telstra is now working to fix issues that are affecting EFTPOS services around the country this afternoon.
"Stores are continuing to trade as our teams are still able to process payments manually at this time. We'll provide another update when we know more", Telstra said in a post on social media.
The nation's big four banks and major supermarkets were among those caught out in the failure, which affected some EFTPOS terminals and access to ATMs across the country.
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Westpac Banking Corporation, National Australia Bank Ltd and Australia and New Zealand Banking Group had also reported problems with automated teller machines and payment processing.
CommBank is also advising not to call if you are now having issues.
The latest problem comes just weeks after the Reserve Bank of Australia revealed that outages had soared by 40 percent and warned banks and telcos about the dangers of ageing infrastructure. We're sorry for the impact and inconvenience caused. We are working closely with external providers as to when these services will be restored and we will continue to update our customers as a priority.
"We apologise to our customers affected by this. Rest assured we are urgently looking into this and will have further updates soon", the company wrote on Twitter. She added that the bank's call-centre is experiencing a "higher than normal" call volume and said there is no need for retail or business customers to call the bank.
"The cause of the problem is under urgent investigation".
ANZ says it is also investigating the issue.