Rebecca Barry talks to Kiwi opera singer Kristen Darragh about her drive to perform around the world.

Twice a week New Zealand opera singer Kristen Darragh boards a train in Berlin and heads to her next audition, hoping this will be "The One". Her whole routine is geared around this process, her every movement pinned on her dreams of scoring a job in a German opera house. It's not a life for a quitter. For the last six months she's been turned down enough times to put anyone off.

"Of course I've had moments where I've questioned it. Should I be here?" says Darragh, 30. "But there's just no consideration for me to give up, or that I'm going to do something else with my life. And I feel quite blessed that I've come this far."

Early this month she will prove just how far when she plays Amastre in the New Zealand Opera and Melbourne's Victorian Opera co-production Handel's Xerxes, as part of the biennial Auckland Arts Festival. It's two years since she was named NZ Opera's Young Artist for 2009, an esteemed position created to give young singers stage experience - and an income. During that year, Darragh performed as Zulma and the understudy of Isabella in L'Italiana in Algeri and Olga in Eugene Onegin.

This time she will play the jilted princess, betrothed to King Xerxes of Persia, whom she has caught trying to seduce his brother's girlfriend.

Those who know her say Darragh is on the verge of a successful international singing career, which, in the world of opera, is akin to winning gold at the Olympics. At 30, Darragh is a baby, who hopes that by the time her voice has matured - some time in her 40s - she'll be considered for the great roles. She has Amneris from Aida in her sights.

Amastre is an exception, a meaty part requiring a young singer capable of projecting a fearsome rage, with the technical proficiency to remain within the precise constraints of baroque, a genre not given to flowery expression.

"It's such a terrific part, and Kristen plays it with such passion," says Xerxes' Australian director, Roger Hodgman, who has worked with as many actors as singers during his 30 years directing opera, musical theatre, film and TV.

"Her arias are so animated and strong, which is good because the character is driven to fury. But Kristen also has a softness and vulnerability. She's gorgeous, so open. As a director you love people who are eager to try stuff, someone who has opinions about the material."

We're in the NZ Opera rehearsal space in Onehunga. John Verryt's revolving set has transformed the back half of the warehouse into Persia. Darragh presides over it incongruously in black jeans and costume heels. Even in this semi-mufti ensemble, hands clasping a makeshift dagger, she is explosive. In her most crazed and vengeful aria, Amastre is determined Xerxes will be hers and she's going to get revenge.

Xerxes is a soap opera of lust, sibling rivalry and comedy, set to baroque, or as John Rosser, the opera's chorus conductor, calls it: "18th century rock music that sounds like drum 'n' bass when the lutes kick in".

Darragh was offered the role as it suits her fulsome mezzo soprano, so she has flown home especially for the two months it has taken to stage the production. Offstage, her intensity still lingers.

"I'm not an angry person at all but of course we all have anger in us to access," she says, in a velvety speaking voice. "I have a propensity for drama, I like the roles that have an extreme sense of feeling. Mostly the negative feelings like anger, despair, sadness. It feels like somewhere you can really go and explore, you're going there to the absolute edge."

Darragh has always been committed to reaching the absolute edge of her potential. A dramatic child, for a long time she dreamed of being an actress. She joined her local Takapuna theatre group, played Toad of Toad Hall in Wind in the Willows at age 9 and, in later years, won parts in TV shows Riding High and Shortland Street. She also took singing lessons at school, sang in the choir, performed in musicals and competed in local singing competitions. The first opera she saw was Turandot, during a school trip. It moved her so much that at 15 she decided, without question, she would be an opera singer.

"[Opera] is on another plane, especially when you get it right. It's like I go to another place, and it's an amazing place to be, it's surreal, it's otherworldly. I love that," she says. "Because then you come back to your normal life. There's a quote: 'after the ecstasy, the laundry'. Opera's the ecstasy. If that can be your day job, that's pretty cool."

At 19, while studying for a BA at the University of Auckland, Darragh became the youngest singer to join the NZ Opera Chorus, an elite group of about 65 singers recruited for large opera productions. Soon after she started going to Auckland-based vocal coach, Frances Wilson.

"Kristen was funny, everything always had to be this great performance, even though she didn't always know how to make the right noises," says Wilson. "But she knew what she wanted to sound like."

Progressing quickly, Darragh made her debut with the NZ Opera in 2003, playing Fyodor in Boris Godunov, aged 23. The following year she left New Zealand to study at the Royal Academy in London. If you don't study somewhere as prestigious as that, says Wilson, you have no hope of making it as a star.

But Darragh always had more than hope. She dedicated every moment to singing and soon became the envy of her fellow students when she won the lead role in Benjamin Britten's The Rape of Lucretia, a dream role, she says, because of what happens in the title - Lucretia then tries to kill herself.

Near the end of her four years there she was awarded a Dame Kiri Te Kanawa Foundation grant, and took part in the Solti Te Kanawa Accademia di Bel Canto, a summer school Te Kanawa set up with Sir George Solti. Darragh also received personal tuition from the Dame.

"She was great, she'd invite me out to her house and we'd spend the whole afternoon singing. It wasn't intimidating, even though the idea of it was. But actually once you start working she's an incredible artist and makes you feel very comfortable. She's passionate about helping young singers. She's a very strong woman and you have to be to become that great."

Darragh has a similar steeliness. Her gentle speaking voice is coupled with regal posture and nothing but focus in her eyes. Her passion and tenacity are so palpable it's hard to imagine her not making it. Her strength, she says, comes from her parents' constant encouragement, a growing independence from living overseas and the fact that she's had to fight for success.

"I wasn't plucked out of college and thrust into Covent Garden. I've had to continually believe in my ability, even when there's not always been proof, and just work and work. I have to keep fighting which feels like good training for what's to come. Because if it's all internal you don't need it from the outside."

If that sounds Tony Robbins-esque, it could be because Darragh is a qualified teacher of an international self-improvement course called Avatar, in which paying students learn how to harness their own power and "create" their desired futures.

It seems to be working for Darragh. She credits the course for helping her to stay grounded and allowing her to step out of the "self-absorbed" world of the singer. That gig, along with financial assistance from a generous sponsor, also allows her to pursue her dream in Berlin.

It was her New York-based music teacher, Patricia McCaffrey, who suggested she move there. The US is an even more competitive a market to break into, says Darragh, and Berlin, with its German opera houses and cheaper accommodation, not to mention proximity to McCaffrey's "Berlin Mafia", a network of her own approved singing teachers, would make it a worthwhile move.

She lives in Berlin-Mitte, an artsy area in the east of the city, with Kiwis, visual artist Nicky Broekhuysen and violinist Jenny Banks. Travel is not on the agenda, unless it's work-related. Last month Darragh says she got to see Bucharest and a "great concert" at the Romanian Athenaeum, when she scored a singing gig there. Aside from the daily three hours of German lessons, her life is all music.

"My purpose is the career at the moment. So unless I'm taken somewhere with that, I don't go on holiday."

Nor does she have time for a relationship, unless it's with someone equally as focused on their career.

"Normality?" she laughs. "What is that?" Her ultimate goal is to become a high-profile singer with a freelance career that allows her to travel the world. Rather like her idols Dame Kiri and US soprano Patricia Racette.

"I think Kristen is on the verge of something very interesting, a very good career," says Wilson. "This verge could take two to three years, or six months, you just don't know. It's a long job to produce a big voice. You must slowly tune the instrument, you can't force it ... "

She listens and takes advice humbly and eagerly, and hungrily wants it."

That eagerness is vital in a climate that has seen opera houses - purveyors of one of the most expensive cultural genres - struggling to survive.

"I'm not giving up now," says Darragh. "I've come so close and that's what seems to keep me going. I get better all the time. That's the other thing, you have to enjoy the process ... I'm at the stage now where I'm so hungry for work, for experience, to be immersed in this profession ... I'm just champing at the bit."

Xerxes is at the Civic Theatre, The Edge, 7.30pm March 2-5; 5pm March 6.