When Karen Tyrrell was 26, she landed a great job in Bermuda, and headed off to the tropics with her boyfriend (now husband) Kieran. For four carefree months she had the time of her life, zipping between work and the beach on her moped.

Then things took a slightly John Grisham-esque twist. Tyrrell discovered that her employers - hedge fund administrators Hemisphere (now Bisys) - had an ulterior motive in bringing her to Bermuda.

Although she wasn't aware of it at the time, Tyrrell had been hand-picked by Hemisphere, and her time in Bermuda was actually a trial run to decide whether to make her a further offer. Clearly she passed the test with flying colours because after just four months, she was asked to return to Ireland to set up a new office.

So in 1999, at the tender age of 27, Tyrrell gave up her sun-drenched lifestyle and returned to her home town of Dublin to set up Bisys's Irish operation from scratch. "I was nervous, I'll be honest," she says.

Never having pitched to potential clients before, she now found herself presenting to groups of high-flying investment managers, having to ask what seemed like very trivial questions about their requirements. But the feedback was great, and new business poured in thick and fast.

"The most challenging thing was wearing so many hats," she recalls. "Presenting to clients, knowing I've got to go out and do valuations, then interviewing somebody to do the job I'd been doing that morning.

"There was many a night in the early days where I thought - I can't breathe, there's so much work to do."

Nevertheless, within the first year, not only did the business grow to about 70 people, but Tyrrell also fitted in buying a house and getting married.

Growing up on the north side of Dublin ("the right side!"), Tyrrell was "always burning the candle at both ends". She won the All-Ireland javelin throwing championship for two years running and was always out playing soccer or basketball.

Being brought up in a "very, very ordinary life" meant that she learned "a lot of old-fashioned values with regard to working hard and studying hard".

Although her Leaving Certificate results would have earned her a place in college, she headed straight into the workforce. Joining the investment division of Irish Life at 18, she put herself through college at night to qualify as an accountant.

Now, as managing director of Bisys Hedge Fund Services - Europe and the mother of two young children, Tyrrell is still juggling many roles.

"The biggest challenge, my own personal challenge, is I feel like I've two jobs," she says. "There's this job Monday to Friday, and then I have my children before work, after work and at weekends." What tends to get sacrificed, she says, is her own personal time and her sporting interests.

Having said that, she ran her second marathon this year, fitting in training sessions before work, late at night after the children were in bed, on some lunch breaks and on Saturday mornings. "That was a major challenge," she admits.

When Bisys opened in Dublin in 1999, it was one of the first back-office hedge fund administrators to locate here.

"There weren't very many administrators around town doing what we did," she says. Since then the floodgates have opened and roughly 50 competitors have entered the market. But Tyrrell explains that there's more than enough work for everyone. "There's room for everybody from a business perspective. The problems are at a staffing level."

The fight, she says, is not getting the clients, but rather selecting those who have the potential to grow and add assets.

"The art isn't actually winning a presentation, unfortunately. The art is picking the right one, backing the right horse," she says. "You're selecting your client in a lot of cases. It's gambling. We track our rate of success with regard to the horses that we back."

Staffing has been a crucial issue for all financial services players, and Bisys is no exception. "There's less supply than demand, so there is a bit of a hostage situation going on."

Spiralling labour costs are becoming a problem in the sector. "It's a bit of a vicious circle. As house prices continue to rise, staff become more demanding," she says. "I think that will hinder the business growing because Ireland will just become expensive as a place to do business."

Tyrrell estimates that salary levels in Bisys have been pumped up "a couple of hundred per cent" over the past five years. But she notes that the increased expense hasn't resulted in a higher calibre of person. "If you then look at our fees and our revenue, they haven't gone up in proportion, because there's only so much further [ they] can go before hitting a ceiling."

Like many operators in the funds industry, Bisys has decided to look outside Dublin to resolve its staffing issues. An office was set up in Waterford last year, which now has about 55 employees.

So what does the future hold? "Controlled growth," Tyrrell predicts. She compares her management philosophy to her marathon training: "Keep the head down, don't worry about the competition . . . and hope it works out!"