Some nurses in Belgium have taken part in assisted suicide without the patient's request or consent, according to a new study published in the Candadian Medical Association Journal.

Authors of the study said more than 100 nurses went beyond their legal role and may have under-reported their involvement.

According to researchers, the nurses may have acted according to their patients' wishes even if there was no explicit request.

Euthanasia is legal in Belgium under a doctor's supervision and the patient's consent.

"We should take a warning from this that wherever you draw the line, people will go up to it and beyond it," Dr Peter Saunders, Director of the pro-life group Care Not Killing, told The Christian Institute.

"Once you have legalized voluntary euthanasia, involuntary euthanasia will inevitably follow," he added.