Two thirds of the decline was in Victoria which has had to implement strict lockdown rules to contain COVID-19.
In year-to-date percentage terms Victoria is still the worst state but Tasmania and the Northern Territory are not far behind.
In contrast the ACT sale volumes have risen, 24% compared to last year.
The Federal Camber of Automotive Industries has implored the Victorian Government to allow Melbourne Metropolitan vehicle and motorcycle dealerships to open up.
The FCAI says that dealerships follow best practice COVIDSafe protocols.
The trend is not just COVID-19 as sales have declined in Australia for the last 29 months but the pandemic is pushing some dealers to the wall the FCAI says.
Im David Brown
Motoring Minutes are heard around Australia every day on over 50 radio channels through the Torque Radio network. Motoring Minutes have an average daily audience of over 150,000 listeners. Motoring Minutes are also broadcast as part of Overdrive Radio Program, which is broadcast through the Community Radio Network across Australia and has a weekly audience of over 450,000.