Teachers may be forced to surrender pay points to avoid unemployment, the Government has admitted.
Junior education minister Cheryl Gillan acknowledged that attempts to change teachers' pay and conditions raised difficult issues for staff moving schools or returning to teaching.
But she said the proposals, from the School Teachers' Review Body, had arisen out of concern about expensive teachers being priced out of the jobs market.
It has recommended that staff moving schools, returning to teaching or who have retired waive experience points in return for a job. The moves are being contested by the six teacher trade unions.
They have jointly taken legal advice on how to challenge the Government and are consulting the Equal Opportunities Commission, as they believe the changes are discriminatory because the majority of teachers who would be affected would be women returners.
Mrs Gillan, however, said the proposals would enable retired teachers to make themselves more attractive to employers.
Her comments came in a speech to a National Association of Schoolmasters Union of Women Teachers equal opportunities conference last week.
The speech was delivered by a civil servant as Mrs Gillan had to appear in the House of Commons.
In her speech during an NASUWT debate on ageism, she stated: "Talented older teachers should not be made to feel that they have to make way for others who may not be as good at their job.
"If governing bodies have to make someone redundant - and I don't deny that they sometimes do - I urge them to make that unpleasant decision on the basis of what is best for the pupils, not on what is the easiest option."
She acknowledged that the STRB proposals raised difficulties. "For example, job applicants may feel pressurised into surrendering pay points. But they may feel that that is better than unemployment."
Mrs Gillan rejected claims it was a gender issue because it affected those with discretionary points for child rearing.
"I suspect there are more who worked in industry before finding their vocation as teachers, and received discretionary points for that experience.
"More relevant for today may be the question of retired teachers returning to the classroom. Good teachers should stay on as long as possible, but if they do retire prematurely I for one see nothing wrong if they come back on an occasional basis or as supply teachers.
"The proposal will make it easier for them to do that by giving them the ability to make themselves more attractive to employers."
Her comments went down badly with delegates who believe schools have now entered the redundancy season and that the jobs of older, more experienced and expensive staff are on the line.
And they blamed local management of schools and its formula which pays average, rather than actual, teacher salaries.
In Norfolk, the conference heard, one headteacher had already told one of his regular supply teachers that another supply teacher was prepared to work for less money.
Elsewhere in the county, staff were considering whether to fight for the jobs of two older teachers, or let them go knowing that the jobs of three younger ones would then be safe.
Chris Keates, a member of the NASUWT national executive, said: "As soon as we get into the redundancy season, anyone over the age of 50 starts to feel uncomfortable in the staffroom when people start looking in their direction.
"We forget that many 50-year-olds have still got heavy commitments - a second family, older children. They are not in the financial position of coming to the end of their career."
The Government has a ministerial campaign in favour of older workers and is hoping to persuade employers that age discrimination at work has no place in a prosperous economy.
Michael Meacher, Labour's employment spokesman, said that a Labour government would introduce legislation, and added: "There is a plague of insecurity affecting almost all the workforce now."
Meanwhile, Mrs Keates said advertisements for teaching jobs would continue to ask for "young, enthusiastic, committed teacher with sense of humour".
"That's the sort of discrimination that's always there," she said.