Primary teacher-training numbers should be cut by half and secondary numbers by a quarter by 2010, according to a review of provision in Wales.
The current seven training providers should be pared down to three regional schools of education in north, south and west Wales.
And three-year undergraduate courses leading to qualified teacher status (QTS) should be phased out in favour of one-year postgraduate certificate in education training (PGCE).
But current spending on teaching-related courses should be maintained to develop new "pre-professional" degrees offering a broad preparation for working in education - whether as a teacher, early-years support worker, counsellor or youth worker.
In his report, Professor John Furlong, of Oxford university, says: "Wales cannot justify training teachers that it does not need, especially as it now has to pay for such courses itself."
The review group took into account pupil population changes in Wales at a national and regional level, teacher retirements and turnover, NQT supply, cross-border transfers, and "a significant margin of error" when working out the proposed cuts in trainee numbers.
But the size of them has surprised educationists, and some have questioned the reliability of the data used by the review group.
Geraint Davies, secretary of teachers' union the NASUWT Cymru, said the review had been radical. But the level of proposed cuts were "foolish and short-term, because in a few years time we could be facing a shortfall of teachers in Wales".
Dr Janet Pritchard, Bangor's head of education, said: "This will cut the teacher workforce to the bone, and that's very worrying. We don't collect sufficient data to make these kinds of decisions."
She also opposes plans for Wales to train teachers just for Welsh schools, saying the exchange of students and teachers with England is "very valuable for the profession".
The Furlong review could mean an uncertain future for staff in university and college education departments. It recommends ending initial teacher-training at the North East Wales Institute of Higher Education.
NEWI's provision, and that at Bangor and Aberystwyth, would be transferred to a new north and central Wales school of education.
A south-east Wales school would bring together provision at University of Wales Institute of Cardiff and Newport university. And Swansea Institute of Higher Education and Trinity college, Carmarthen, would collaborate under a south-west Wales school.
In all three cases, the Furlong review says the existing providers should decide together how they will rationalise courses.
But it emphasises that current levels of spending on teacher-training should be maintained, to support the proposed "pre-professional" education degrees - and ensure the new PGCE-only departments are viable.
Professor John Parkinson, head of Swansea school of education, is concerned about the impact of dropping three-year undergraduate courses with QTS, particularly for primary teachers, who have to teach across the curriculum.
"How can we be sure that these new 'pre-professional' courses are going to produce good-quality primary teachers?" he said.
"There is a lot of knowledge which we are able to cover in the current degree. We may be able to do that on pre-professional courses, but not to the same extent."
Other recommendations include:
* improving on-the-job training by creating a nationally managed Welsh internship scheme;
* developing performance indicators for initial teacher-training;
* carrying out an annual survey of Welsh NQTs;
* establishing a national and regional forums on ITT; Jane Davidson, education and lifelong learning minster, will make her formal response to the report later. But she told TES Cymru that she was committed to ensuring the teacher-training sector in Wales remains viable.
And the proposals - especially for pre-professional degrees - offered the opportunity to develop training for other key workers needed in schools, she added.
"The children's commissioner has said we need more people with skills as counsellors, and we are going to need new professionals for the foundation phase."