Supporters of voluntary euthanasia have applauded a decision for a state parliamentary inquiry to investigate "end of life choices".

Voluntary euthanasia is likely to be explored in detail by the inquiry, which will report back by May next year.

Greens MP Colleen Hartland said voluntary euthanasia had been taking place "in the dark".

"There are doctors out there assisting people to die," she said. "I'm hoping there will be several doctors that will give evidence about what they've done."

Ms Hartland, who supports voluntary euthanasia, said she hoped doctor and euthanasia advocate Rodney Syme would also give evidence.