The rapid decline of traditional letters due to emails has led the Australia Post to announce 1,900 job cuts over the next three years, authorities said on Friday.

The Australia Post said losses in its mail delivery business were approaching 500 million Australian dollars ($387 million) this financial year, reported Xinhua news agency.

The volume of ordinary mail is expected to fall by more than 10 per cent, and the Australia Post has warned it will report its first company-wide financial loss in more than 30 years.

Australia Post managing director Ahmed Fahour said the decline in the mail deliveries is now critical.

"We have reached the tipping point that we have been warning about where without reform, the business becomes unsustainable," Fahour said.