An advisory panel in Canada has recommended that terminally ill children as young as 12 years old should be given the choice of physician-assisted death.

The panel's recommendation is based on the "mature minor" doctrine that says minors can make their own medical decisions if they know the nature of their sickness and the effect of their decision, the National Post reported.

"That's already well established in our system," said ethicist and panel member Arthur Schafer, director of the Centre for Professional and Applied Ethics at the University of Manitoba.

He said "the idea of an arbitrary age limit, and people suffering intolerably and waiting days, weeks or months to die because they haven't reached that limit, seems morally unacceptable."

Schafer said there's no age restriction when it comes to taking off a respirator or ventilator, refusing antibiotics or stopping kidney dialysis.

"End-of-life decisions are being made every day in Canada by mature minors. Doctors make decisions about competence and capacity all the time," he said.

The nine-member panel said there should not be any "arbitrary age limits" for physician-assisted death which, it averred, should be based on maturity and mental competence, not age.

"A five-year-old? A seven-year-old? They would never be seen as having the capacity or competence for making these decisions," said co-chair Maureen Taylor, widow of Dr. Donald Low, who recorded a video to plea for legalised assisted death days before he died in 2013 of brain tumour.

Taylor said theoretically, a 12-year-old can have the maturity to make such decision.

"I could definitely see 12-year-olds having that capacity, and I could see 16-year-olds not have that capacity," she said, adding that decisions could be made on an individual basis.

Last February, the Supreme Court of Canada ruled on the Carter vs. Canada case, granting mentally competent adults having "grievous and irremediable" conditions the right to a physician-assisted death. The court gave the federal government one year to draft a law.

The panel, which is assisting provinces and territories on physician-assisted deaths, said in its report released last week that the court did not define "adult." The age of majority in most Canadian provinces is 18.

"We just didn't feel that to make an arbitrary decision that, at 17 years and 364 days you wouldn't meet the criteria, but the next day you would, we felt that wasn't the way to go," Taylor said.

Schafer said "setting an arbitrary age limit seems cruel and unfair."

The panel spent three months consulting experts and organisations in Canada. The report presented 43 recommendations including lethal injection and doctor-prescribed drug overdose.