The public sector pensions dispute remained deadlocked tonight despite a move by the government to improve arrangements for more than half a million NHS workers.

Andrew Lansley said that under “improved” proposals, 530,000 staff will not need to pay any more into their pensions next year because the threshold for freezing pension contributions will be raised from £15,000 to £26,557 for 2012-13.

The change will protect lower-paid staff in the health service, with increased contributions distributed among higher earners, said the government.

Unions accused ministers of trying to “mislead” workers and criticised the timing of the announcement ahead of fresh negotiations which were held today.

Unison’s head of health Christina McAnea said: “The proposed increase in pension contributions will still hit more than half of all NHS staff who are already struggling to cope with the pay freeze and rising inflation.”

Unite said thousands of middle-income NHS workers will be subject to a “smash and grab” raid by the Treasury under the latest proposals, which the GMB said were not enough to settle the pensions row.