Voluntary euthanasia campaigner Dr Rodney Syme has expressed ‘‘grave concerns’’ that people with mental illnesses may be accessing information on how to kill themselves through websites and seminars run by Dr Philip Nitschke.

His comments follow condemnation, by groups including the Australian Medical Association, of Dr Nitschke’s actions in helping a 45-year-old man without a terminal illness to die.

Perth man Nigel Brayley, who ended his life using a euthanasia drug, was being investigated by police over the suspected murder of his wife.

Dr Nitschke said Mr Brayley had not lost his capacity to make a rational decision. He said he provided support to Mr Brayley to end his life and did not believe he had any obligation to refer him to a GP or psychiatrist.

Dr Syme said the case reinforced his long-held concerns about Dr Nitschke providing information to people through websites and seminars without any knowledge of their mental state.