That's according to calculations by former Labor economist Dr Brendan Long, maths he said he is "happy to defend" and based off his own analysis of the growth of similar programs running in parts of the US, Belgium, Holland and Switzerland.

Dr Long, of the Australian Centre for Christianity and Culture at Charles Sturt University, shared his insights as an advisor to Victorian Deputy Premier James Merlino, who led an unsuccessful attempt to block euthanasia laws in the state.

Disability groups appearing before the inquiry on Friday were spilt on the issue. The ACT Disability, Aged and Carer Advocacy Service said that, as risky as the legislation could be for those with disabilities, leaving them out altogether was not the solution.

Chief executive Fiona May said their voices were already regularly ignored by the health system.

But Lives Worth Living, a national network of leading disability rights advocates, urged the ACT to reject euthanasia for all people with disability as dangerous.

Convenor Craig Wallace said for people with disability "euthanasia ... holds a horror in our memory" as forced programs had been responsible for the murder of thousands in Nazi Germany and spoke to a culture that still saw the suicide and even murder of those with disabilities as a release.

The health system was hostile to disability and diversity, he said, leaving many cut off from the necessary screening and treatment to prevent terminal disease in the first place.

Some couldn't get on exam beds at their local GP because they were too high, he said, and common procedures such as an x-ray or colonoscopy were virtually impossible for a number of people with disabilities in the ACT, including himself.

One woman he knew had gone 20 years without a pap smear because there weren't any accessible services available.

This led to people with disability being pushed to the "front of the queue" for options like assisted dying, even if laws were carefully restricted to terminal illnesses, Mr Wallace said.

Until people with disabilities were on an equal footing with the rest of Australia in terms of access to healthcare, he said euthanasia posed an unacceptable risk.

"Legalising the killing of sick and disabled people in these times is a dark crevasse we should not fall through," he said.

Professor Michael Quinlan, Dean of the School of Law at Notre Dame University, said assisted dying laws were vulnerable to slippage. As the option was normalised, the types of cases accepted often grew, he said.

But the Health Care Consumers Association said some restrictions in existing programs around the world were too rigid, pointing to the new Victorian euthanasia legislation that requires a 12-month prognosis.

Both Ms May and the association supported the idea of implementing a pre-approval program where people could log their interest in being offered a euthanasia option down the line to minimise delays.

Gev Khambata of the association said, "If [you're] going to die in 12 months, but the whole process probably takes about six or eight months [there's] no real sense."

Ms May stressed that regular conversations with someone who had no stake in the outcome would still be essential to give people opportunities to change their mind.

She recounted how her own father-in-law had eventually been forced to die in hospital, after controlling his health care plan every step down the path of a long illness.

"I could not praise the hospital where he was enough but it was still five days of watching him slowly die and I would not wish that on anybody ever again," Ms May said.

"He made his choices all the way along, but at the end he didn't have a choice."