However, Teach First NZ chief executive Shaun Sutton says that of the 15 inaugural alumni from its 2012 class, 13 have stayed in New Zealand, and all of those are continuing to teach.
More than half remained in low-decile schools. Where they have moved out of poorer communities it was largely due to a lack of teaching positions at those schools because of falling rolls.
Mr Sutton said he was hoping the highly selective process would help to shift the status of teaching, to make it seem more desirable for highly motivated and ambitious graduates.
"At the moment it's seen as more of a last option at university - and that's not how it is in other countries," he said.
"We want to show that it's a rewarding career - the reward is in the impact you can have, in making meaningful impact as an effective teacher."
The focus on low-decile schools aimed to help in getting the best teachers in front of those kids, in schools which struggled to retain high-quality staff.
Alfriston College principal Robert Solomone said his school was one of the first to get the programme, and was reaping the benefits.
"They have picked some very high calibre young people who would otherwise not have thought about getting into the teaching business," Mr Solomone said.
"They are already highly qualified and are showing a real passion for the job. They want to try new things and are doing it well."
He said the school's board was committed to the programme and would continue it. Teach First NZ is now aiming to grow to 60 incoming participants by 2019, and to expand further than Auckland and Northland.
To qualify for the programme, applicants needed to meet a range of achievement, leadership and attitude criteria, as well as having a bachelor degree with strong subject knowledge in the topic they wished to teach.
Proud to make a difference where it matters most
After three years of teaching, Ruby Hale has decided it's the small things she finds most rewarding.
"People stop me for a chat. I'm starting to teach brothers and cousins, so I really feel part of the community. And I've been here long enough to see some real progress."
Ms Hale, 25, signed up for the Teach First NZ programme while studying economics and geography at university. The programme gives graduates a chance to get paid while they become teachers at low-decile schools.
"What really appealed to me was the emphasis on equality. Education is something that should give everybody an opportunity to get somewhere in life."
She says that while she knows she is making a difference teaching at Alfriston College in Manukau, there are some kids who remain out of reach, and she wants to do further research on how to help them.
"We talk all the time about disengaged kids. Lots of it is about building a relationship, that's where you get the success."
Ms Hale says she will stay in the job for at least two more years, and then hopes to do some kind of policy work as well to address the problems facing those hard-to-reach kids.
While the job is demanding - a lot is social work as well as teaching - she says it's worth it, especially because of her talented colleagues.
"It takes a particular kind of person but from where I'm standing I don't see a lack of talent in the low-decile schools. I feel really humbled to be here."
