The government has delayed its plans to announce new pensions contribution rates for public servants by three months.

In a letter to the TUC, the chancellor George Osborne said he would postpone announcing increases in the March Budget, as originally scheduled in the comprehensive spending review.

The date would be extended until June to allow for discussions on the increases, likely to average 3%, between the government, TUC and relevant trade unions.

Osborne said the government remained committed to phasing in savings on public service pensions of £2.8bn a year as from April 2012, which he said was “essential to meeting the government’s deficit reduction plans.”

He told TUC general secretary Brendan Barber that the proposals from government would be based on protection for low earners and “a greater contribution” from those on higher salaries, which would be “progressive”.

The desired £2.8bn savings would be distributed between the various public schemes, he said, and the Cabinet Office and the chief secretary to the Treasury will monitor the talks for each scheme.

The chancellor added that the government accepted that public service pensions should “continue to provide a form of defined benefit and that there must not be a race to the bottom of pension provision.”

He said: “We want public service pensions to be a gold standard while at the same time accepting that they must be affordable.” Ministers would be seeking “full engagement” with TUC unions on the recommendations in the final Hutton report, expected shortly before the budget on March 23.