By 1966 Australia was described as BMC's leading world market.
The 1800 was introduced in Australia in November 1965 as the Austin 1800, with a Mark II version being introduced in 1968.
Australian-produced vehicles started out with a claimed local content of 65–70%, along with an undertaking from the manufacturers to raise the level to 95% in line with government requirements by the end of 1968.
 Initially the cars were generally identical to their British contemporaries; however, the local production was quickly modified to suit the harsher roads and climate of Australia.
Modifications to the British Mark I design included raised suspension trim height, the provision of a large, heavy sump guard, and better sealing against dust.
The Australian Mark II was notable in retaining the lower final drive ratio of the Mark I's manual transmission (but not the lower second gear), and, with the exception of the initial production run, was fitted with a dual-circuit hydraulic braking system manufactured locally by Paton's Brake Replacements (PBR) Pty.
Ltd. Despite offering the safety of a dual-circuit system, it was generally held to be inferior in performance to the earlier Girling equipment.
The Australian Mark II was also originally fitted with an alternator manufactured locally by Electricity Meter & Allied Industries Limited (EMAIL), a company better known for its kilowatt-hour meters and household appliances.
In the event of failure, most EMAIL alternators were replaced by Australian-made Lucas units.

A version unique to Australia was the Austin 1800 Utility, a coupe utility produced from 1968 to 1971.
Over 2,000 examples were built.
The Utility was released near the end of the first series in July 1968 and most of the examples produced were therefore Mk IIs.
A cab chassis variant was also offered.
The 1800 Utility was given the model code YDO10.

Per capita, the Australian model sold better than anywhere else in the world.
Ironically, it represented the tail-end of the popularity of British-designed cars in Australia.
In the Australian market, it offered a roomy and advanced 4-cylinder alternative to the popular 6-cylinder models such as the Holden Kingswood, which used conventional engineering based on American principles.
Some versions badged BMC Freeway (a name previously used for a six-cylinder Farina model in Australia) were exported to New Zealand, which also assembled UK-made Austin and Morris 1800s in separate plants.

As a one-off engineering prototype, to test production viability, an Australian 1800 Mark II body with subtly extended front guards and modified front internal structure was fitted with an early Rover 3.5 litre V8 mounted in the "North-South" position in the engine bay and then through a complex mechanical system, drove a heavily modified version of an "East-West"-mounted Borg Warner 3-speed automatic gearbox and Austin FWD differential.
This car became Australia’s first locally-made FWD V8 car.
The car was built by BLMC (Australia) at its Victoria Park works at Zetland, New South Wales.
Mass production costs and general viability of the V8 "1800" were felt to be excessive, and the project was shelved, preference being given to the Australian Leyland P76 project.
Some reports state that the vehicle was eventually shipped to British Leyland in the UK and never seen again, while others claim it was simply broken up at the end of its testing by Leyland Australia.
By 1966 Australia was described as BMC's leading world market. The 1800 was introduced in Australia in November 1965 as the Austin 1800, with a Mark II version being introduced in 1968. Australian-produced vehicles started out with a claimed local content of 65–70%, along with an undertaking from the manufacturers to raise the level to 95% in line with government requirements by the end of 1968.  Initially the cars were generally identical to their British contemporaries; however, the local production was quickly modified to suit the harsher roads and climate of Australia. Modifications to the British Mark I design included raised suspension trim height, the provision of a large, heavy sump guard, and better sealing against dust. The Australian Mark II was notable in retaining the lower final drive ratio of the Mark I's manual transmission (but not the lower second gear), and, with the exception of the initial production run, was fitted with a dual-circuit hydraulic braking system manufactured locally by Paton's Brake Replacements (PBR) Pty. Ltd. Despite offering the safety of a dual-circuit system, it was generally held to be inferior in performance to the earlier Girling equipment. The Australian Mark II was also originally fitted with an alternator manufactured locally by Electricity Meter & Allied Industries Limited (EMAIL), a company better known for its kilowatt-hour meters and household appliances. In the event of failure, most EMAIL alternators were replaced by Australian-made Lucas units.
A version unique to Australia was the Austin 1800 Utility, a coupe utility produced from 1968 to 1971. Over 2,000 examples were built. The Utility was released near the end of the first series in July 1968 and most of the examples produced were therefore Mk IIs. A cab chassis variant was also offered. The 1800 Utility was given the model code YDO10.
Per capita, the Australian model sold better than anywhere else in the world. Ironically, it represented the tail-end of the popularity of British-designed cars in Australia. In the Australian market, it offered a roomy and advanced 4-cylinder alternative to the popular 6-cylinder models such as the Holden Kingswood, which used conventional engineering based on American principles. Some versions badged BMC Freeway (a name previously used for a six-cylinder Farina model in Australia) were exported to New Zealand, which also assembled UK-made Austin and Morris 1800s in separate plants.
As a one-off engineering prototype, to test production viability, an Australian 1800 Mark II body with subtly extended front guards and modified front internal structure was fitted with an early Rover 3.5 litre V8 mounted in the "North-South" position in the engine bay and then through a complex mechanical system, drove a heavily modified version of an "East-West"-mounted Borg Warner 3-speed automatic gearbox and Austin FWD differential. This car became Australia’s first locally-made FWD V8 car. The car was built by BLMC (Australia) at its Victoria Park works at Zetland, New South Wales. Mass production costs and general viability of the V8 "1800" were felt to be excessive, and the project was shelved, preference being given to the Australian Leyland P76 project. Some reports state that the vehicle was eventually shipped to British Leyland in the UK and never seen again, while others claim it was simply broken up at the end of its testing by Leyland Australia.
BMC ADO17