Former prime minister Gough Whitlam has been hailed a Labor hero by the party's federal MPs.
Mr Whitlam died on Tuesday at the age of 98.
"Vale Gough Whitlam - a legend who shaped modern Australia," Labor frontbencher Anthony Albanese tweeted.
Shadow treasurer Chris Bowen described Whitlam as a "Labor Hero".
"A loss to the nation. RIP Gough," he wrote on Twitter.
Western Sydney MP Ed Husic thanked Whitlam for "dreaming big and believing our country could always strive for better".
Matt Thistlethwaite praised the former leader as "Australia's great reformer and visionary".
Joel Fitzgibbon said Australia had lost one of its greatest.
Deputy opposition leader Tanya Plibersek said Mr Whitlam was an inspiration.
She recalled his generosity in guiding younger members of the party and advice offered over a cup of tea at his Sydney home.
Ms Plibersek also paid tribute to his legacy and policies, some of which - like free university education - were controversial.
"He is the iconic figure for making brave policies stand," she told Sky News.
"He's an inspirational figure in that way."
In an article for the Guardian, former prime minister Julia Gillard has described Mr Whitlam as a great leader and a great person.
"Gough will live always in our nation, which he transformed throughout his long public life," she wrote.
Mr Whitlam lived on in Australia's universities, its health system, its suburbs, its family law, its relationship with China and its multicultural society, she said.
"I honour Gough as a man of the highest political courage. A giant of his era. He was truly prepared to commit and see what happens. He transformed Australia and we are in his debt."
Greens leader Christine Milne wrote "RIP Gough Whitlam. A very sad day".
"He was a larger than life figure whose leadership profoundly changed the nation for the better," she tweeted.
Palmer United Party leader Clive Palmer sent his condolences to the Whitlam family.
"He was a man of integrity who achieved a lot for our nation. He must never be forgotten by Australians," he tweeted.
Governor-General Peter Cosgrove expressed his condolences to the Whitlam family.
"Mr Whitlam was a towering leader of his time who made a significant contribution to the life of our nation and his legacy endures today," he said in a statement.
"Lynne and I extend our deepest sympathies to the Whitlam family at this sad time."
Victorian Opposition Leader Daniel Andrews says Victorian-born Mr Whitlam left Australia a fairer place, with universal health care and universal rights.
"Today we remember a man who lived for one century, but whose legacy will live on for many more in the annals of our nation and the hearts of its people," the state Labor leader said in a statement.
"In just three years, his government changed us all."
Mr Andrews said Mr Whitlam devoted his best years to the Labor movement.
"He did more than anyone to give our party a purpose and a place in the homes of Australian families.
"We remember a soldier and a statesman, a father of four and a father of a nation."
South Australian Premier Jay Weatherill said Mr Whitlam inspired a generation.
"For the first time in our history we had a leader who showed us that government can use its power to improve the lives of all Australians regardless of their race, their gender, their birth or their wealth," he said in a statement.
"He was, and remains, my inspiration."
Victorian Premier Denis Napthine said Mr Whitlam was a political giant.
"Gough Whitlam was a giant in Australian politics," he said.
"He certainly heralded a number of significant reforms during his time as prime minister and his long contribution to the Australian political life."
Dr Napthine highlighted ending conscription and Australia's involvement in the Vietnam war, Australia's first interactions with China and the introduction of universal health care as reforms for which Mr Whitlam will be remembered.
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