A number of banks are experiencing technical issues with their ATMs and EFTPOS terminals, with Telstra saying they are "looking into the issue".
Westpac and Commonwealth Bank customers have taken to Twitter to complain that ATMs terminals were unable to accept card payments.
Westpac said its teams were working on the issue. "We're aware some branches, ATMs & services in Sydney metro are non-operational due to a broader network failure in the region," the bank tweeted.
Commonwealth Bank said its services were "currently impacted by an issue" with one of its telecommunications providers.
"We apologise to our customers affected by this. Rest assured we are urgently looking into this and will have further updates soon," the bank said in a statement.
"We can confirm the CommBank app and NetBank are still working.
"We know there are some issues with the following services: CBA ATMs, CBA EFTPOS terminals, some in branch services as well as issues logging onto the CommSec website.
"Due to this issue, we are experiencing higher than normal calls into our call centre. There is no need to call us if you are experiencing problems with these services."