The government has calculated the move from RPI to CPI indexation for occupational schemes could reduce the value of pension rights by as much as £76.6bn over 15 years.
Steve Webb has said the government will not give private sector schemes the power to override scheme rules to shift from RPI to CPI indexation.
Defined benefit scheme deficits have rocketed by about 50% over the past four years jumping from an average of £55bn to £87bn, figures show.
An industry-wide consultation on the RPI to CPI switch will be issued tomorrow, Steve Webb says.
The top 100 UK firms' defined benefit schemes knocked £42bn off their combined deficit over the last year, Pension Capital Strategies research shows.
More than 10 million people will see their state second pension hit by the Consumer Price Index switch by the end of this parliament, the government says.
Pension reform is continuing at a relentless pace but can the industry keep up? Helen Morrissey reports
The switch from RPI to CPI for pensions indexation will give members a lower outcome over the long term but gives better consistency, Steve Webb says.
A group of 13 opposition MPs have called on the government to delay switching to the CPI index for public sector pensions until further research has been conducted into pensioner spending.
Pensioners groups are uniting in London to urge the coalition government against switching the pensions indexation to the consumer price index, as it will push millions into poverty.