Betty Cuthbert was Australia's greatest advocate for multiple sclerosis and her death is a huge loss for the country, MS Research Australia CEO Mathew Miles says.

Mr Miles says the champion track runner "went in to bat" for multiple sclerosis sufferers and her contribution to MS research has been immeasurable.

"We would never have been able to achieve the sort of fundraising that we have over the last 13 years without Betty Cuthbert and that, in turn, has led to some really significant Australian breakthroughs in multiple sclerosis research, undoubtedly," Mr Miles said.

First diagnosed with MS in the '70s, Cuthbert was there at the charity's inauguration alongside then prime minister John Howard in 2004, and a research fellowship was even named after her.

"She loomed large in the genesis of MS Research Australia," Mr Miles said.

"She was a great advocate for MS and as her wonderful athletics career naturally stopped, she really did put a huge amount of energy, time and dedication to raising awareness about MS, so it's a massive loss," he told AAP.

"I think a lot of people's recognition and understanding of what multiple sclerosis was really came from knowing or having a visibility of Betty Cuthbert," he added.

MS is a disease of the central nervous system which eats away at the protective covering of nerves, leading to symptoms such as poor coordination and balance, fatigue, bladder incontinence and memory loss.

In Australia, MS affects over 23,000 people.

While there is currently no known cure, there's been an incredible explosion in the understanding of MS as a result of recent research which has led to improved diagnosis and treatment.

Before Cuthbert was first diagnosed with MS, researchers knew "nothing" about the genetic side to the disease.

"We now know 150 genes that determine the susceptibility to MS," said Mr Miles.

"That's what research has brought us, this drastic change in how you treat MS and then directly on to that, the outlook for people with the most common form of MS," he said.

WA Premier Mark McGowan has offered a state funeral for Cuthbert.

"She was a wonderful Australian, a golden girl from a golden era in Australian sport," Mr McGowan told reporters.

Tributes pour in for Cuthbert

Raelene Boyle, three-time Olympic silver medallist (told the ABC) - "She was so humble and nice. She didn't have any airs and graces about herself because of what she had done. She was easy to talk to, easy to approach and gave great guidance."

John Coates, Australian Olympic Committee president - "Betty battled her illness for many years and showed tremendous courage, but more importantly she always managed to smile. Betty was a member of a unique band of athletes who inspired thousands of Australians."

Marlene Mathews, Cuthbert's greatest Australian rival - "I have never met anyone that had such great faith and determination. It was this faith that kept her going for so long and through the most difficult times."

Cathy Freeman, 400m Olympic gold medallist - "It's a very sad day, there's no doubt about it. Betty is an inspiration and her story will continue to inspire Australian athletes for generations to come. I'm so happy I got to meet such a tremendous and gracious role model, and Olympic champion."

Robert De Castella, former world champion marathon runner (told Fox Sports) - "As a young fellow, I remember Betty taking me under her wing and giving me advice. Not only was she a tremendous athlete, but she was a wonderful contributor to our country and the sport."

Malcolm Turnbull, Prime Minister - "Rest in peace Betty Cuthbert - an inspiration and a champion on and off the track."