Further Government restrictions on higher-rate tax relief risk damaging long-term savings, insurers argue.
Today's Pre-Budget Report revealed higher-rate tax relief restrictions - originally announced in April's budget - will now include employer contributions and affect those with relevant income of £130,000 and over, rather than the previously announced figure of £150,000 and over.
The Report also states: "Tax relief will gradually be tapered away so that above £180,000 it is worth 20%, the same rate received by a basic-rate income taxpayer."
As many as 150,000 additional people will be caught out by the extension of higher-rate tax relief restrictions, according to Standard Life.
Rachel Vahey, head of pensions development, Aegon, says fears last April's announcement could be the "thin edge of the wedge" in eroding long-term tax incentives have been realised today.
"We all recognise the Government faces some very tough decisions to reduce public debt. But it must stick to its side of the bargain to avoid putting long-term saving at risk.
"Pensions are still a good deal for many people but they need to have faith the Government won't move the goal posts again in the future. Politicians must oppose further tinkering otherwise there's a serious risk people won't believe any assurances that pensions are safe in their hands.
"The Government's own pensions reform proposals, introducing automatic enrolment from 2012, recognise the fact we need to get more people saving more money for their retirement.
"But the Government risks undermining this by removing the stability and consistency necessary to give people the confidence to save. The A-day agreement, introduced barely three years ago, was meant to give that stability, together with much needed simplification of the pensions tax system.
"Today pensions simplification has been dealt a further blow."
Friends Provident is also critical of the way it says "pensions are being treated as a political football in a game where the goalposts are constantly shifting."
James Ward, director of UK corporate, Friends Provident says: "This latest move will add yet another unwelcome layer of complexity to pensions in the UK.
"At a time when we should be pulling out all the stops to encourage people to save, the Government is instead creating barriers to prevent it.
"We need to highlight the benefits of saving into pension schemes and this constant tinkering around the edges is chipping away at consumer confidence and has to stop."
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