James Wallner, the man who successfully took on two governments to win financial aid for victims of "Mr Fluffy" asbestos, has died in Canberra.

The 54-year-old veterinary scientist was diagnosed with malignant pleural mesothelioma last year and passed away in a Canberra hospice on Friday.

Mr Wallner contracted the disease after growing up in a house tainted with loose-fill asbestos insulation, sold by the company that became known as Mr Fluffy.

His brother Bruce said on Saturday that his death was tragic and preventable.

Bruce said there was "a relief that his suffering is at an end" but James' death "should never have happened".

Family friend James O'Loghlin paid tribute to Mr Wallner, who had dedicated the last nine months of his life to fighting for justice for asbestos victims.

"Mesothelioma is a dreadful disease and James Wallner faced it with courage, dignity, and his unique and wonderful sense of humour," Mr O'Loghlin said.

"He always said his attempts to get a compensation scheme set up was not just about him, and he was acutely aware of what he saw as his responsibility to other 'Mr Fluffy' mesothelioma victims who would follow him.

"He was warm, funny, and compassionate. Everyone liked him, many loved him and we will miss him deeply."

Living with toxic asbestos in the roof

As a toddler, James Wallner, along with his three brothers, had played in a pile of the asbestos that had been stored in his garage during home renovations.

Mr Wallner told the ABC last year that, for decades, his family had put up with "dust" raining from the ceiling of their home in the Canberra suburb of Campbell, but thought little of it.

His mother had even sealed up a kitchen ceiling vent with aluminium foil, to stop the material contaminating their food.

But unlike those who contract mesothelioma through James Hardie 'bonded' asbestos products, Mr Wallner had no avenue for compensation.

It was a legal loophole, because the Mr Fluffy company had folded decades ago.

All victims' families to get financial help

When he was diagnosed, Mr Wallner joined with family and friends and began to lobby the ACT and federal governments to financially support all people who contracted the incurable disease.

Late last year, the ACT government awarded him a $125,000 "act of grace" payment to cover his rising medical costs.

And late on Wednesday, the federal Health Minister confirmed it would co-fund a broader, $16 million asbestos assistance scheme, to support all eligible victims of the Mr Fluffy debacle.

The Wallner family home was one of about 1,040 Canberra houses fitted with the deadly ceiling insulation.

At least four other men are known to have died from asbestos-related disease after living in a Mr Fluffy home, and it is believed their families will be invited to lodge retrospective claims for financial support once the scheme is operational.

Despite the Mr Fluffy homes being "cleaned" during an expensive federal government program in the late 1980s, many of the houses remained contaminated with asbestos.

In 2014, the ACT government announced it would spend $1 billion buying back and bulldozing the affected homes.

When Mr Wallner was diagnosed with mesothelioma at just 53 — about 20 years younger than the average age — his oncologist was puzzled.

"His first question to me was, 'Have you had exposure to asbestos?' And I said, 'I grew up in a Mr Fluffy home,'" Mr Wallner told the ABC last year.

"He looked a little blank at that point, so it was pretty obvious I think to me."

Aid announced in Mr Wallner's dying hours

Just two months ago, speaking to the ABC's 7.30, Mr Wallner feared his fight for a compensation fund might come "too late" for him.

The federal government confirmed the announcement of the asbestos support fund was rushed through, just hours before Mr Wallner was moved to a Canberra hospice.

His brother, Bruce, had broken the news to a critically ill James.

Speaking after the announcement, ACT Labor senator and former ACT chief minister Katy Gallagher paid tribute to Mr Wallner.

"His story has really been so powerful in convincing Commonwealth officials that they needed to step up and help the ACT government with a fund like this."

Campaigner united two governments

The Mr Fluffy saga had been mired for years in political controversy, with neither the federal nor ACT governments prepared to accept legal liability for its effects.

The insulation had been installed in Canberra homes between 1968 and 1978, when the Commonwealth had responsibility for the ACT.

In 1989, when the territory was given self-government, the ACT government also inherited the homes contaminated with Mr Fluffy.

Today, the ACT government points out that the new financial assistance scheme is neither compensation nor an admission of liability.

For the families who will live with Mr Fluffy's grim legacy, the wording may be irrelevant.

But ACT Liberal senator Zed Seselja said this week that funding the scheme was about the Commonwealth "taking responsibility" for the mistakes of the past, when governments had ignored health warnings about asbestos products.

In the final few months of his life, Mr Wallner had managed to do what many before him had tried but failed: to get both governments to set aside politics and put the focus on those who would die from living in a Mr Fluffy home.

He could have simply accepted his deadly diagnosis and suffered in silence.

Instead, through his advocacy and agitation, he won a significant victory that will support victims of Mr Fluffy for decades to come.

In doing so, Mr Wallner dragged two government to a public acknowledgement that — regardless of any outstanding legal arguments — supporting those victims and their bereaved families is simply the right thing to do.

He is survived by his wife Linda and their two sons, Max and Charlie.