According to media reports, the glitch allowed users to see other customers' details by altering a shipping identification number that appeared in the URL of a transaction. Click and Send was designed for online postal documentation -- such as preparing items sold on auction site eBay for delivery.

Learn how smart CIOs are

IDC Australia senior market analyst Vern-Harn Hue told Computerworld Australia that the glitch could potentially be a "big blow" for Australia Post as it seeks to position itself as an enabler in the digital economy.

"As increasingly more Australians transact, trade and consume online, digital trust and security is paramount," he said.

"Consumers need to know that they are backed by a trusted source to handle their personal and financial information and AusPost will have to work hard in order to win over consumers trust."