All NAB branches across Australia have closed and been evacuated after a physical security threat.
NAB released a statement to its customers on Twitter.
"Unfortunately we have had to close our branches temporarily due to a physical security threat," the statement said.
"As always the safety and security of our customers and colleagues is our priority.
"We are working closely with police and will provide an update as soon as we can."
The bank has not determined the location or nature of the threat.
More to come