The scrapping of the General Teaching Council for England (GTC) will erase the "absolutely essential" register of teachers and create excessive red tape for schools, heads have warned.
Information needed to predict demand for new teachers and the numbers of unqualified staff working in schools will also be lost, according to heads' unions the NAHT and the Association of School and College Leaders.
The Department for Education has announced that the GTC's successor will only deal with disciplinary functions and no longer register details, including qualifications and experience. Currently that information is accessed by thousands of headteachers during checks before employing new staff.
The DfE has said that the new system will mean a "reduction in time and effort" for teachers. But GTC chair Gail Mortimer said: "I would strongly question any assumption that registration simply costs time and money - in fact, it can present a net saving in these areas.
"The 630,000 employer checks of teachers' registration status undertaken online through the GTC last year saved a great deal of manual checking of teachers' qualifications and school-to-school record checks."
Brian Lightman, ASCL general secretary, said it was "absolutely essential" that a database of teachers' records was maintained.
"It's of huge importance for everyone involved in education. It's needed to predict teacher supply and availability. The Government needs this to plan ahead," he said.
"We must have these records available - we need all this information to be accessible. Schools need to be able to access it. This will be especially important when the Government reforms teacher training and more providers are in the system."
NAHT general secretary Russell Hobby said the decision could lead to an increase in bureaucracy. "There needs to be a clear record of teachers' qualifications; schools will always have to verify these," he said. "At the moment they can just check the register, but in future they will have to seek references. There's a danger the Government are just shifting the responsibility on to schools - the register might go but headteachers will always need to make checks."
The end of the GTC will also mean, however, that teachers will no longer have to make a contribution to registration fees. At present, it costs #163;36.50 a year to register, although teachers in maintained schools are reimbursed most of the charge.
A DfE spokesman said: "After the abolition of GTCE, there will be new, simplified arrangements - and as part of that new funding arrangements. The Government will set out details in due course."
SPENDING TO SAVE - Abolition 'will cost #163;8m'
Axing the GTC will cost at least #163;8 million, according to analysis in the education white paper.
The body, which is due to be closed in March 2012, will be replaced with a new slimmed-down organisation that only deals with disciplinary cases.
The successor will cost #163;8 million a year to run, half the amount the current GTC costs.
The Department for Education says the changes will save #163;112 million between 201011 and 201920.