Australia Post has kicked off a major overhaul of its financial accounting systems in a move that could pave the way for the oft-mooted privatisation of its lucrative parcel division.

Internal documents seen by Fairfax Media reveal preparations have been made to create a separate legal entity for courier operation StarTrack and the parcels business, and to clean up its financial records – important groundwork for any future sale.

The postal workers union fears Australia Post is preparing for a sale, and Fairfax Media can reveal that late last year senior Australia Post finance staff were already working on a restructuring operation called "Project Bridge" to update internal financial reporting systems.

According to the documents seen by Fairfax Media, one benefit of Project Bridge is that it "enables financial management of two legal entities by July 2016". And it "enables a future simplified separation program" and "could be used if ownership separation is accelerated".