The letter, signed by the likes of Nick Farr-Jones, George Gregan and Michael Lynagh, alleges mismanagement at RA, which is struggling to keep rugby afloat during the global sporting shutdown.
"In recent times, the Australian game has lost its way," the Sydney Morning Herald newspaper quoted from the letter.
"It is a defeat inflicted not by Covid-19, or an on-field foe, but rather by poor administration and leadership over a number of years.