She describes The Gift as an exploration of the tension between professional ambition and parental responsibility shot through with a classic story-telling technique: strangers meet and discover they have more in common than first appears.
In this case, wealthy older couple Sadie (Peirse) and Ed (Napier) meet Martin (London) and Chloe (Hill) at a luxurious Pacific Island resort and hit it off, despite coming from completely different worlds. When Martin saves Ed's life, out of gratitude the older man offers to grant the young couple whatever they wish for but neither couple anticipates just how weighty the request will be.
The play deals with marriage, parenting, creativity, and what happens when the balance between duty to oneself and duty to others tips too far in one direction. Murray-Smith says the play can be interpreted quite literally or as a metaphor to examine where we've got to as a society.
"Speaking in general terms, it's particularly about the role of creativity, or any preoccupation that overwhelms us, and the ways we have to balance our ideas of art - or the pursuit we are passionate about in life - with our responsibilities as human beings."
To say it involves children is to reveal little, given that everything today that involves children seems to create a dilemma for their parents and admitting to parental confusion or even ambivalence is viewed as monstrous.
"As parents, what you learn is that no matter how much ambivalence you feel about the day to day 'job' of parenting, you love your children," says the mother-of-three who has, throughout her working life, balanced writing with hands-on parenting.
"Children set your nerve-endings alight: pain is more painful, joy is more joyful and that's what you buy into. The colours of life are painted more vividly, but I think it's easier to talk about the 'tough stuff' - to complain about the denials, difficulties and sacrifices - rather than talk about the joys because they are harder to express without sounding cloying and sentimental."
While it may be funny at times, The Gift is not sentimental. In fact, Murray-Smith says when she finally saw it performed, after being caught up with the mechanics of staging the play, she was shocked by the idea she was putting forward and experienced a strong emotional reaction.
Her family, and the necessity to begin a new project, pulled her through. Indeed, Murray-Smith seems never to be short of an idea to explore. The daughter of literary editor and academic Stephen Murray-Smith, in 1995 she attended the writing programme at Columbia University in New York, accompanied by her husband Raymond Gill, and eldest son Sam, who was just 3 months old.
Having already written a handful of plays, Murray-Smith had been commissioned by Melbourne's Playbox Theatre to produce a work for them. She later told the Columbia University Record that writing was the least of her worries; she was breast-feeding a baby and feeling slightly overwhelmed.
The result was Honour, a four-character drama about a middle-aged writer who leaves his wife and their daughter for a younger woman. Its first public appearance was as a reading at Columbia University with Meryl Streep, Sam Waterson and Kyra Sedgwick. Honour has since been performed in more than three dozen countries, including on Broadway and the West End, and garnered a number of awards. ATC was one of the first international companies to stage the play.
Murray-Smith, meanwhile, has continued writing and her plays now include Rapture, Bombshells, Nightfall, Redemption, Love Child, Flame and The Female of the Species, controversially based on the life of Germaine Greer. The latter was a sell-out for ATC when it was performed in 2008.
It's not intentional, but she believes the clash between the heart and the head, instinct and reason, is a pre-occupation in her work. Those subjects can get weighty so humour has become an essential device in her writing.
"The older I get, the more I find humour is essential, especially in drama and tragedy. The job of a dramatist is to take the audience into territory they don't necessarily want to go into and humour is the playwright's greatest ally in this endeavour."
What: The Gift
Where and when: Maidment Theatre, September 13-October 6.