Queensland premier Annastacia Palascczuk confirmed the passing of the ALP heavyweight on social media.
"Bill was revered," the premier said.
"He started life in the shearer's shed and eventually became National President of the Australian Workers Union.
"He will be remembered as one of Australia's greatest union leaders."
Mr Ludwig was awarded the Medal of the Order of Australia for service to industrial relations through the Australian Worker Union in 1997.
In 2001 was awarded the Centenary Medal in recognition of his contribution to Australian society.
"Bill Ludwig was a giant of the labour movement in Australia," the AWU said in a tribute.
"If there is one value that defined Bill, it was his unwavering view that workers should be able to organise collectively and stand up for their interests against bad bosses, and if need be, against politicians.
"In this way, Bill personified the very soul of the AWU."
Born in the central west Queensland town of Longreach in 1934, Mr Ludwig was raised in Ipswich.
He began his working life as a shearer in the 1950s and took part in the bitter 1956 shearers' strike to fight when shearers and pastoralists clashed over wages and conditions.
After two decades in the sheep industry, Mr Ludwig became an AWU organiser in the 70s before becoming South Western District Secretary.
The 'diligent, strong-willed union official' was appointed Queensland secretary in 1988 before being anointed as the AWU National President in 2001.
Outside of unionism and politics, Mr Ludwig was an avid supporter of horse racing, serving on the board of Queensland Racing.
The beloved father, grandfather, and great-grandfather died in Brisbane on April 11, surrounded by family.
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