TNT, which has run up total losses of Adollars 393m ( pounds 172m) in the past two years, said David Mortimer would take over immediately as managing director. Mr Mortimer was previously group finance director.
TNT said Sir Peter, 68, asked the board to accept his resignation after 18 months of immense effort spent on improving local and overseas operations.
Sir Peter wanted to concentrate his efforts on Ansett Transport Industries, where he is joint chairman and joint managing director, TNT said. Ansett operates the loss-making Australian domestic airline Ansett Airways in a 50-50 joint venture with Rupert Murdoch's News Corporation.
Sir Peter will continue to be a director and deputy chairman of TNT, the company said.
His retirement has been a regular rumour in equity markets for the past few years.
This month TNT reported an Adollars 195.42m net loss for the year to June after a Adollars 197.18m loss a year earlier. The company said net borrowings fell to about Adollars 1.38bn from about Adollars 2.46bn and it was confident of a return to profitability in the current year.
Sir Peter, who was born in Austria to Hungarian parents, arrived in Australia soon after the end of the Second World War and built TNT into the country's largest transport company.Reuse content