Westpac customers are now able to begin accessing correspondence from the bank, including statements, through Australia Post's MyPost Digital Mailbox.
Westpac is the first bank to sign on to the platform, and joins 45 other Australian businesses and government-owned organisations already using the service, including Telstra, AMP, Sydney Water, and the federal government's MyGov.
The bank initially signalled that the Digital Mailbox option was going to be made available to its customers last June, when the two companies signed a strategic partnership.
Westpac managing director and CEO Brian Hartzer said it offers customers options when it comes to managing their finances.
"The MyPost Digital Mailbox gives customers more flexibility in how they want to receive information from Westpac, while also providing additional functionality. Today's announcement is another example of how Westpac continues to look at new ways to give customers greater flexibility through online channels," he said.
Digital Mailbox was launched in 2012, and was designed as a free service for all Australians to receive statements and bills digitally, as well as store documents in a private cloud service hosted in Australia.
Australia Post's managing director and CEO Ahmed Fahour said customer registrations for the Digital Mailbox are up 86 percent in the past eight months.
The government-owned organisation has increasingly been focused on providing online solutions to cope with the decrease in traditional letter deliveries.
Last September, Australia Post announced that its profit after tax for the 2013-14 financial year was down 34.5 percent, mainly due to its mail business seeing a significant drop in letter volumes.