After 36 years as an actor Maggie Kirkpatrick might question the wisdom of her career choice - but that hasn't quashed her passion for excellence. Even if it means losing her hair.

For a recent film role, Maggie Kirkpatrick agreed to have her head shaved. At 56, this was no Demi Moore publicity stunt. For the sake of one scene in Stephan Elliott's Priscilla follow-up, Welcome To Woop Wop, she embraced the clippers and shaving cream for her craft.

"It was the most liberating thing I've ever done," says Kirkpatrick, the actor most famous for her sinister turn as lesbian prison warder Joan "the Freak" Ferguson in the television series Prisoner.

One can't help but imagine that the nasty "screw" with a leather glove fetish would have been made doubly effective with a touch of this bald routine, but even without it, Kirkpatrick made resonant work of the role, which was surprisingly three-dimensional for its time.

Judging by her recent escapades with a razor, she has lost none of her appetite for stretching the limits. Having delved into the gamut of television, film and stage offerings spanning a 36-year career, her range and commitment as an actor is in no doubt.

Even so, when you confront her in the flesh, it's the Freak that you first see. Even softened by a chambray shirt and straw sun hat, her eerily familiar piercing glance and her deep, well-enunciated tones are present - and a little bit terrifying.

Scratch the surface, though, and Kirkpatrick exudes none of the authoritative assuredness of her Prisoner days. She seems slightly knocked around by her life and career. She admits to being uncertain about the merits of acting and often battles with the blows to the ego it constantly dishes out.

"I get a little more pessimistic as I get older with this business called acting," she confesses.

"You spend X amount of years honing a skill and when you reach an age where you think you've really git something to offer, invariably that's the time nobody wants you. It's hard to maintain the self-esteem, it's hard to maintain the joy for the skills that you've acquired and, frankly, if  I knew how to do something else, I would."

Later, Kirkpatrick will sink her teeth into the folly of acting again. "It's a silly thing to do. Why put myself through 36 years of this? How stupid is that? It's just a childish thing of getting dressed up in silly clothes and putting on funny hats and being someone else, really, isn't it? No, I don't think it's a good life, but it's too late to turn back." Only her disarming twinkle-eyed smile suggests that she is not entirely serious.

Besides, this is an "up" time. Her phone finally rang, after what she considers an unacceptable silence. "I want to be wanted, like all actors do," she concedes, lamenting the dearth of roles for women of a certain age. "When it does happen it's hard to take and it's harder to take as you get older. The resilience doesn't seem quite as great."

It was Perth Theatre Company on the line, inviting her to play Betty in its production of Kay Mellor's play A Passionate Woman  (which runs at the Playhouse Theatre from November 13 to 29). It's dubbed a Shirley valentine-esque story of a woman who has lived a confined domestic existence all her life, then makes a stand late in life and breaks out in pursuit of passion.

It's a role Kirkpatrick thinks will go into her private collection of favourites. "There's an awful ot of Betty in a lot of women my age," she says, before drawing some personal comparisons with the character.

"I'm passionate about things. As I get older there are probably fewer friends, but I am passionate about the closeness of those precious few. I'm passionate about excellence in work, and I strive for excellence. I'm passionate about my grandchildren, and what the future might hold for them. I'm passionate about the survival of the species, the planet... One acquires a greater sense of mortality when you've got grandchildren. It makes death just a little more real."

Clearly Kirkpatrick is in something of a reflective state. Earlier this year she staged a one woman show in Sydney, playfully titled The Screw Is Loose, which documented her life and career in broad brushstrokes set to music. Quite a milestone for someone who, even as a child when her head was "stuck in the clouds dreaming of Hollywood musicals", only ever wanted to be a nurse.

She admits now she's lost some enthusiasm for acting, but only due to lack of opportunity. "It makes me frustrated that I'm not constantly honing my skills," she says. "When I was 20 I expected at 56 to still be working and constantly learning and embracing all sorts of ideas and emotions that go with interesting people's work.

"When the opportunity presents itself then it's a double-edged sword because I'm scared. I wonder if those skills are rusty."

There were no such concerns when she nipped off to London's West End to vamp it up in a musical version of Prisoner Cell Block H last year, and again on a UK tour earlier this year.

Prisoner still screens to 1.6 million viewers five nights a week in the UK and, because there are no royalty payments coming her way, Kirkpatrick feels justified in "jumping around the stage like a fool" in the highly successful stage spoof which earned her enough money to keep the wolf from the door at home.

"It's exploited me for years but I in turn have exploited it," she says of the TV show about which she now feels "very ambivalent".

"It gave me four and a half years' steady employment, but out of 36 years (that's) not a big bite, is it? I'm not ashamed of the character, but there are other things that are dearer to me."

Her stint in Prisoner earned her the enigmatic tag of gay icon, which she believes to be largely an invention of the UK tabloid press. "The majority of my fan letters come from little old ladies in Sussex," she says, but she is grateful, nevertheless, for the profile the tag has afforded her fundraising efforts for people living with AIDS - "some of the bravest people I've ever known".

She was married for 15 years - "to Mr Kirkpatrick", now deceased - and has a daughter, Caitlin, and two grandchildren. She now lives outside of Sydney, where she spends much time in her garden indulging her passion for native plants.

For a moment she might seem altogether too normal to be involved in head shaving activity on a project like Elliott's Welcome To Woop Woop, which she describes as "anarchic, subversive madness". But its curious blend of Rodgers and Hammerstein music, dead kangaroos, red dirt, wigs and fart jokes sits perfectly well with Kirkpatrick's palpable zest to perform - given the chance.

"The real joy is in discovering the process of finding your way to the final, joyous moment that tells the audience what ot's all been about," she says, as if drawing a parallel between performance and life. The tentative, pessimistic bits that have crept into her own, it seems, are only as strong as her next dry spell. "I love rehearsals. I'm terrified of performing. But only for a minute or two."