Malcolm Fraser has been remembered as a "leader of compassion" for his post-political crusade for social justice and savage critique of Australia's treatment of asylum seekers.

CARE Australia, founded by Mr Fraser in 1987, has said its current operations, which includes the clean up in Vanuatu post Cyclone Pam, is the legacy of the former Liberal prime minister's fight against poverty and injustice.

CARE chief executive Julia Newton-Howes said Mr Fraser's 17-year association with the charity, including more than a decade on the board, shaped the organisation.

During that time he travelled overseas to highlight humanitarian crises in Rwanda, Somalia, Iraq and Bosnia.

"He really felt strongly about global poverty and the crises that push people into poverty and ruin lives," she said.

Greens senator Sarah Hanson Young remembered Mr Fraser turning up in the public gallery to support her in a speech against the Gillard government's move to reopen detention centres in Nauru and Papua New Guinea, with the support of the Tony Abbott-led opposition.

Mr Fraser went on to launch Senator Hanson Young's 2013 re-election campaign.

"He made it clear to me that my contribution was important and he wanted to see it continue. It's a very humbling experience having a giant of Australian politics say something like that to you," she said.

Mr Fraser made it clear that there was a personal toll in actively campaigning against the party he led as prime minister.

"He was an old school political leader who believed that ideas and individuals are more important than the doctrine party line," she said.

"After he sat in the gallery during my speech he said 'you tell me what you want and I'll do it, I will back you'. And he did. People like him don't say things unless they mean them."

The Fred Hollows Foundation paid tribute, saying the Fraser government provided the funding for the first National Trachoma and Eye Health Program, which Fred Hollows oversaw.

"This program was really revolutionary and helped to drive Indigenous health on to the national agenda for the first time, by highlighting the shocking health standards in many Indigenous communities," said the foundation's chief executive Brian Doolan.

"It made Australians sit up and reflect on our values, and the kind of nation we wanted to be.

"Malcolm Fraser called him to a meeting in Kirribilli House and the funding, through the Royal Australian College of Ophthalmologists, was secured," he said.

Mr Fraser was critical of the Howard government's approach to humanitarian issues. Former Labor prime minister Gough Whitlam once remarked that Mr Fraser had "replaced me as public enemy number one in the demonology of the Australian right wing".

In 1979, the Fraser government established the Australian Refugee Advisory Council to advise it on the settlement of refugees.

On Friday, Mr Howard honoured Mr Fraser's actions on behalf of Vietnamese boat people and African poverty as prime minister and his enduring opposition to apartheid.

"He will be remembered by many people for the generosity of his response after the end of the war in Vietnam to Indo-Chinese refugees taking many tens of thousands of them … from refugee camps in the region," Mr Howard said.

"In part, that made up for the quite shameful treatment in my view of many Vietnamese people closely associated with the Australian effort in Vietnam in the dying months of that war by the Whitlam government."

Mr Abbott added his voice to those praising Mr Fraser's resettlement of Vietnamese refugees, who he said had "added a rich dimension to our national life".

The Prime Minister also raised Mr Fraser's environmental credentials. Sand mining on Fraser Island was banned by the Fraser government and areas like the Great Barrier Reef added to the World Heritage List.

Mr Fraser quit the Liberal Party over Mr Abbott's refusal to support emissions trading but his fiercest criticism of the current government was reserved for its treatment of asylum seekers.

His last opinion piece written for Fairfax Media was a strident defence of Human Rights Commissioner Gillian Triggs and her report into children in detention.

"The government is concerned to make sure the law and the courts cannot restrain it in the exercise of its harsh policies," he wrote.

"So, many years of development of administrative law and international law are wiped out by this government and the Australian Parliament."

In a statement, Ms Triggs said Mr Fraser was "a towering figure in human rights".

"I have known Malcolm for 40 years. He was always generous with his time and demonstrated a great ability to resolve difficult issues," she said.

"He loved to tell stories about his days in Parliament and had a lot of wisdom about what was achievable in public policy."

Former Labor prime minister Paul Keating said Mr Fraser bore "no truck with race or colour and no tolerance for whispered notions of exclusivity tinged by race".

In a statement, Communications Minister Malcolm Turnbull said Mr Fraser would be remembered for introducing the Aboriginal Land Rights Act in 1976 and for his fight against racism.

"In office and out of it he showed himself to have a big and compassionate heart," he said.

"Modern Australia would be very different without his vision and leadership.

"Whether one agreed with him or not, in whole or in part, one thing was never in doubt. Malcolm Fraser was a passionately patriotic Australian with a big, liberal vision for our country and its people."

Follow us on Twitter