National Australia Bank branches are set to reopen this morning after a hoax bomb threat forced the country’s third largest bank to close its entire network on Wednesday.

The bank received the security threat early in the afternoon and soon after closed all branches and ATM machines attached to banking premises.

“Unfortunately we have had to close our branches temporarily due to a physical security threat,” the bank told customers on its Twitter page.

“This includes commercial offices where they are co-located with branches.

“Where our ATMs are located onsite at a branch we are also taking them offline.

“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.”

At about 6.50pm last night, the bank notified customers on social media that investigations by state and federal police had found the security threat was not credible.

“We are pleased to advise it is safe to return to NAB branches and business banking centres tomorrow from morning,” the bank said on Twitter.

“The latest advice from State and Federal police is that the physical threat is not credible and has been deemed a hoax.

“Thank you for your patience.”