The Department for Education and the Cabinet Office confirmed plans to make changes in April -- changes unions said were "unfair and unacceptable" and being imposed without agreement, the BBC reported Friday.
Contributions to pension plans by teachers and civil servants will increase, the government confirmed.
"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," Schools Minister Nick Gibb said.
Unions said the unilateral move without negotiations was unacceptable.
"The government has confirmed it is prepared to ignore the views of the vast majority of the respondents to its consultation on increasing contributions for civil servants, and will try to impose what it has planned to do all along," a spokesman for the Public and Commercial Services union said.
"This is an unfair and unacceptable tax on public sector workers and we will continue to oppose it."