UK - Personal Accounts will lead to a widespread review of pensions and closure of existing schemes in smaller firms, the Association of Consulting Actuaries (ACA) warns.
It found over two thirds of employers (67%) thought the reforms would lead to a leveling-down of average pension contributions.
And more than half (55%) of schemes failed to meet the exemption test set in the current Pensions Bill, with only 28% of employers expected to use their current pension arrangements as the scheme into which they would enroll employees.
ACA chairman Keith Barton said: "It is very clear there is a huge under-pensioning of millions of employees, but our survey suggests the benchmark set by the government may weigh very heavily on smaller firms."
Standard Life head of pensions policy John Lawson explained the reason many schemes were failing the qualifying earnings test was because the test used banded earnings and non-basic elements of pay such as bonus and overtime.
He said: "The key problem is the exemption test; not the generosity of employers. The government needs to simplify this test so that generous schemes can continue to contribute 8% or more of basic pay."
Conservative pensions spokesman Nigel Waterson added: "This report is further evidence of the very real risk of 'levelling down' of workplace pensions following the introduction of personal accounts.
"We have been warning for some time that many employers may close existing more generous schemes, and that a high proportion of lower-paid workers will opt out of the new system. Ministers need to address these and other issues, and soon."
The Pensions and Lifetime Savings Association (PLSA) has announced it will shrink its board by more than one-third as part of a governance overhaul to make it "agile and more appropriate".
Smaller FTSE 350 defined benefit (DB) schemes were nearly 15 percentage points less well-funded than larger schemes in 2017, according to a Goldman Sachs Asset Management (GSAM) analysis.
The advent of collective pension systems could help the UK avoid demographic challenges which will make it "impossible" for society to help savers in retirement, experts say.