Prime Minister Malcolm Turnbull says Australia has paid "immense and appropriate" honour to Sir John Monash, but he does not wish to create a precedent of posthumous promotion.
Mr Turnbull explained his decision not to entertain a rise in rank a day after opening the Sir John Monash Centre in Villers-Bretonneux in France to honour the Australian war hero.
"We do not have a tradition or a practice of posthumous promotion in Australia, and for all of the reasons the Chief of the Defence Force and others have set out, it's not a precedent that we want to create or need to create," he told reporters in France.
"Monash's legacy speaks for itself and we recognise and honour it in all of its magnificence."
John Monash was a lawyer, an engineer and a general who "revolutionised" warfare amid the horror of the Western Front.
Opening the centre in the general's name, Mr Turnbull praised Monash as an innovator and leader who looked after his troops and won critical battles.
"He pioneered aerial supply drops, and air reconnaissance in near-real time, and showed how to use the trench-busting power of armoured tanks," Mr Turnbull said in his speech at the centre's opening.
"In short, he revolutionised warfare on the Western Front."
In July 1918, Monash led Australian and American infantry in what was then the most sophisticated joint operation in history, involving air drops, artillery and a line of British tanks in the Battle of Hamel.
"He planned to take the village of Hamel in 90 minutes - but was famously three minutes late," Mr Turnbull said.
"That victory put the German army on the defensive right up until Armistice Day."
The prime minister said Britain's Field Marshal Bernard Montgomery later judged Monash to be "the best general on the Western Front in Europe".
"Montgomery said 'the war might have been won sooner, and certainly with fewer casualties' if Monash had been in command of the British armies, too," he said.
"This is why we are naming this centre after Sir John Monash - but it is a memorial to all the Australians who served in this terrible war - from the private soldiers like my grandfather Fred Turnbull, to our greatest general.
"We need to know the appalling suffering of the Western Front."
The $100 million museum was funded by the federal government and aims to ensure the deaths of 46,000 diggers on the Western Front are not forgotten.
