The Government has confirmed it is pressing ahead with raising pension contributions next year for teachers and civil servants, sparking fresh anger from unions.
Ministers were accused of being "unnecessarily provocative" and of imposing the increase for some workers, but a business leader said public sector pensions remained "incredibly generous".
Up to two million workers went on strike last month in protest against the controversial pension changes, and intensive talks have since been held to try to break the deadlocked row.
The Department for Education and the Cabinet Office announced that changes from next year would go ahead, although further talks will be held about future arrangements.
Chris Keates, general secretary of the NASUWT teachers' union, said: "This is a wholly unjustified tax on teachers. Choosing to announce the increase in contributions in the final hours before the national discussions on pension changes have concluded is unnecessarily provocative. Regrettably such ill-timed announcements have been a feature of this sorry saga."
Prospect condemned the decision, saying it meant that increases in contribution ranging from 1.2% to 2.4% for civil servants were being imposed in the year from next April, calling it a "blatant tax".
Most teachers will pay more under the changes, which ministers said were part of the Government's long-term reforms to control the increased costs of people living longer and to "re-balance" the contributions paid by scheme members and taxpayers.
The changes, which will save £314 million from the teachers pension scheme in 2012-13, are part of the wider £2.8 billion savings from public sector pensions by 2014-15 the Chancellor announced in last year's Spending Review, which will see public sector workers pay an average contribution rise of 3.2%.
Schools Minister Nick Gibb said: "Our changes for next year are about keeping pensions affordable for future generations of teachers - while protecting new and low income staff from the biggest contribution increases over the next few years.
"Reforms to public sector pensions are necessary. The overall cost of public sector pensions has risen by a third to £32 billion in the last decade. The cost to the taxpayer of teacher pensions is already forecast to double from £5 billion in 2006 to £10 billion in 2016 and will carry on rising rapidly as life expectancy continues to improve. We've listened carefully to teachers and heads. We've put forward an improved offer on the table and our discussions are continuing."