A deal to keep the retirement age for current public sector workers at 60 will be "honoured", the trade and industry secretary has said.
Mr Johnson reached a deal on pensions last month
Alan Johnson told the BBC an agreement reached last month would be affordable because of "high turnover" of staff.
There have been suggestions the deal may be re-thought as part of the wider development of pensions policy expected after the Turner Commission reports.
Trade unions say they could strike if ministers backtrack on arrangements.
From next year the normal pension age for new staff in education, health and the civil service will rise to 65.
Prime Minister Tony Blair said the "majority of civil servants" would be working under this system "within a decade".
The Turner Commission report on pensions, published on Wednesday, is expected to recommend raising the state pension age to 67.
Mr Blair told the CBI conference in London: "We need a retirement age that begins, over time, to reflect the changing demographic reality."
He added: "We are seeking a settlement for a generation, not for a parliament."
Some business leaders say private firms resent public sector staff being able to retire earlier than their employees.
And Chancellor Gordon Brown, said to be concerned at the possible cost of the public sector pension deal, on Monday said there was "a lot of work to be done" on it, adding that he wanted a debate on a "full range of options".
Asked on Tuesday's BBC Radio 4's Today programme if the government was going to stand by its agreement, Mr Johnson said he could guarantee that.
He said: "The whole thrust of government policy is to encourage people to work longer. Every deal I've reached in my life, as a trade unionist and as a politician, I have honoured."
Conservatives and Lib Dems have accused Mr Brown of attempting to scupper the agreement.
On Monday Work and Pensions Secretary John Hutton said were no plans to revisit the deal, a similar message to that given by Downing Street.