Australia Post's survival hinges on its parcel business after the national postal service notched up its first loss in more than 30 years.
Huge declines in the number of companies and people posting letters have been blamed for dragging the business into the red.
Australia Post managing director Ahmed Fahour said losses from its letters service were so large that it "overwhelmed" profits from its parcels and retail businesses in 2014/15.
He said losses in the mail business grew to A$381 million ($419 million). Since 2008, letter volumes have declined by 36 per cent.
"The company has had to absorb over that same time A$1.3 billion in losses in the letters service," Fahour said. "There is no question that the success we are having with parcels and the rest of our commercial business has had to absorb this.