The chief executive of life and investments provider Royal London has renewed his criticism of proposals to tax income saved into pensions like an ISA.
Phil Loney said the move risks undermining public confidence in long-term saving and "derailing" the government's achievements to date in the retirement sector.
"Nobody should be asked to save for 30+ years without absolute certainty that savings made from their income will not be taxed twice," the group CEO said.
Currently, tax relief on pension contributions is provided upfront as an incentive to keep money locked away until retirement, when contributions are subject to tax.
But Chancellor George Osborne has suggested reversing the system so that pension contributions are made from income already taxed. The savings would then be tax free when withdrawn.
But Royal London said the proposals would be damaging and urged the Treasury to focus its review on the current upfront tax relief model. It suggested an alternative could be a single rate of tax relief on a "2 for 1" basis.
"Creating a healthy savings habit amongst the UK public must be the ultimate goal of all who really care about preserving decent living standards in later life," said Loney.
"This is the rationale for Royal London's strong opposition to the proposal that income saved into pensions should be taxed like an ISA. Nobody should be asked to save for 30+ years without absolute certainty that savings made from their income will not be taxed twice.
"The public will not trust future cash strapped governments to honour any current promise of a tax free ISA style income in retirement."
Loney made the remarks as the group announced its nine-month sales results.
Increased pension sales, particularly a 52% rise in individual pension sales to more than £1.4bn, helped boost the group's overall new business by 35% in the nine months to the end of September, to £4.8bn.
