Griffith calls it "a dark little play in a very ordinary setting - an ordinary suburban household". While he originally set it in Melbourne it could be in pretty much any city

Jack (played by Ezra Bix) and his sisters Vicky (Ruth Katerelos) and Rohana Hayes as Deborah (Rohana Hayes) are gathered in the family home to decide what to do about their mother, who has severe Alzheimer's disease. The unmarried Vicky has been living with and caring for Mum but the older woman's condition has deteriorated to the point where this is no longer possible.

The obvious solution is to sell the house and use what's needed from the proceeds to put their mother into a nursing home where she will receive proper care for the rest of her life..

But Jack, a real estate agent, has another proposal, which he puts to his sisters, regarding their mother.

Griffith says, "He suggests they kill her."

Vicky is adamantly against the idea but Deborah, a single mother, is more willing at least to entertain the possibility. So begins a long, fraught, sometimes acrimonious three-way sibling conversation in which old resentments resurface, secrets come out and various points of view and motivations are explored.

But it's not the characters who decide whether to kill the mother or not. At a certain point, the action stops on stage, the lights are dimmed and the audience is polled -to kill or not to kill? Someone counts the show of hands from behind and then the action carries on as determined by the vote.

Griffith came up with the notion for the play while working in a dementia specific nursing home. He would hear staff members say matter-of-factly in reference to those who were profoundly affected by Alzheimer's, that we should just let them go. But he knew that wasn't an easy decision and in his play he decided to hand it over to the audience so they, like the characters, would be forced to confront their morality.

"It's up to you to decide," Griffith says.

While the subject matter is realistic and serious, Griffith says the play is far from being relentlessly grim.

"On the first night people were laughing all the way through it - it's very funny," he says.

It's a play that provokes a lot of post-performance discussion and sometimes it's what happens offstage that's amusing, at least in retrospect. He remembers at one performance members of an anti-euthanasia group was in attendance and had apparently been assured the vote would be no - but it wasn't and someone cried out, "Oh my God, they're going to do it!"

"They weren't very happy."

And he remembers a mother, about 50, coming to see the show with her son. He voted to euthanise.

"She slapped him and said, "What are you doing, I'm here!"'

Griffith - who says he was pro-euthanasia when he wrote The Magnolia Tree, a redrafting of an earlier play - says he wanted to create a situation that presented a genuinely complicated issue with no simple easy way out for the characters or the audience..

"I personally thought no one would vote for yes," he says,

However, the majority of audiences have done just that. Whether that's reflective of what people would do in real life or simply how they behave in a safely hypothetical situation is hard to say. So far, the play has been presented in small theatres no bigger than 150 seats: Griffith is interested to bring the play to Queanbeyan with its much larger theatre.

"I'm really excited to see how a larger audience votes."

The Magnolia Tree. Written and directed by Michael Griffith. Path2Productions. Queanbeyan Performing Arts Centre. February 14 to 17. 6285 6290 or theq.net.au.