The government-owned company said its net profit fell 56 percent to 98 million Australian dollars in the latter half of 2014 due to a slump in demand for letters.
Like many postal services in developed countries, Australia Post has been struggling to cope as email replaces physical mail. Letter volumes dropped 8.2 per cent in the second half of last year, the sharpest decline since they first started falling in 2008.
"We have been carefully managing the real decline in our letter volumes for the past seven years," he said.
"But we have now reached a tipping point where we can no longer manage that decline, while also maintaining our nationwide networks, service reliability and profitability."
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Fahour called for reform of government regulations that apply to letters, including increasing the price of stamps and allowing a two-speed delivery service.
He pointed to a government-commissioned report last year which predicted that Australia Post will lose 12.1 billion Australian dollars from its letter business and 6.6 billion Australian dollars overall in the next decade without reform.
The Post Office Agents Association Limited, which represents the owners of licensed post offices and mail contractors, backed the call for changed to mail pricing be considered by parliament.
But it also urged the company to diversify its business.
"Ultimately, reform to the letters service is just stemming the bleeding -- Australia Post needs to focus on finding new customers and new revenue streams," it said.