Graduate entry programme struggles to attract trainees from industrial and commercial fields
It is the fast track into teaching, offering on-the-job training for new entrants with a degree.
Yet in parts of Wales - especially the north - there is a lack of interest in the Graduate Teacher Programme (GTP).
Dr John Lewis, director of the scheme, says that of the 25-30 who approach Bangor University's education department every year, six is the highest number to have signed up since 2005.
"It seems surprising more haven't taken advantage," he said. "The population of North Wales is relatively small and geography may be an issue, but in some parts only three or four schools may offer the programme."
The Assembly government wants to welcome mature professionals with experience outside teaching - especially industry - into secondaries. But Dr Lewis said those who do enrol are mostly already in education.
"We've had private sector applicants wanting qualified teacher status; people in further education; graduates working as teaching assistants; and people from abroad," he said. "There just aren't many from outside that background. We think quite a high proportion from industry go through PGCE."
The GTP scheme seeks to attract potential teachers whose home life or location stops them doing traditional teacher training through higher education institutions. Courses last a maximum of a year and are tailored to the individual.
Education minister Jane Hutt announced earlier this month that she will invest more in the scheme. She wants to fill gaps in priority subjects at secondary level. Applicants offering maths, science, modern languages, ICT, design and technology, Welsh, music and RE all get preference.
Mal Davies, head of Willows High in Cardiff and chairman of the General Teaching Council for Wales, said: "We have found the GTP a very good route. It provides a way forward for graduate teaching assistants who have excellent insights into the life of the teacher.
"While I wouldn't want to restrict GTPs to being teaching assistants, classrooms are in a state of continuous change and I think a safer route is to have people who have spent time in them."
The Assembly government also wants a more balanced spread of GTP programmes across Wales. Applications will this year be limited to three per school, with more being encouraged from North Wales and the Welsh-medium sector.
With extra funding, the package will be worth up to pound;18,800 per trainee, paying schools a salary grant of pound;14,400 (up from pound;14,000) and a training grant of pound;4,400 (up from pound;4,300).
In the past five years, the scheme has attracted an average of 68 graduates annually, but the retention rate is unknown. Applications are often made directly to schools, which can offer their own training, externally assessed and approved by the Assembly government. Candidates are thrown in at the deep end: they can spend up to 70 per cent of their time in class.
Jane Priday, one of Willows High's successes, began as a teaching assistant with A-levels. "We sponsored her through the University of Glamorgan and then GTP," said Mr Davies. "The best experience for any trainee teacher is to work alongside an outstanding classroom practitioner."
Dr Heledd Hayes, education officer for the National Union of Teachers Cymru, said: "It's good to have people from various age groups coming into the profession. All our headteacher members say they've had very good experience with graduates on the programme."