Opt-out rates from automatic pensions enrolment are highest among employees aged over 50, a government survey has found.
Research by the Department for Work & Pensions took place among a sample of 50 private and public sector employers covering some 1.9 million workers.
It found 61% were already members of a pension scheme before automatic enrolment began last autumn, and 24% had been automatically enrolled in a scheme. The remaining 15% were ineligible for various reasons.
The opt-out rate was 9% overall, varying between 5%-15% among different employers. Opt-out rates were higher among those aged 50 and over than for other age groups. For the over-50s, opt out was between 25% and 50%, compared with an average 8% opt-out rate among those aged under 30.
According to the DWP, participation in a workplace pension schemes has increased from 61% to an estimated 83%, equivalent to an increase from 1.2 million to 1.6 million people.
The most important factor influencing the level of opt out was contractual enrolment.
Where this was already in place, many of those automatically enrolled had opted out of workplace pension saving in the past and so were twice as likely to opt out again.
In the 19 employers where a workplace pension scheme was in place but workers had previously been required to actively join, 38% were automatically enrolled and the average opt out rate was 8%.
The DWP said it estimated that participation in these organisations increased as a result of auto enrolment from 36% to 71%.
Tom McPhail, head of pensions research at Hargreaves Lansdown, said: 'These results are significantly better than the pre-event forecasts which had predicted opt-out rates of up to 30%.
'These early results are encouraging however there is still a great deal of work to be done, the largest employers were always likely to produce the best results so the real challenges still lie ahead. By the end of 2014 we'll have a much better idea of whether we really are getting to grips with the pensions crisis.'
Malcolm McLean, a consultant at actuaries Barnett Waddingham, agreed that a 9% opt-out rate was 'very encouraging'.
He said: 'If it were to continue at or anywhere near that level would represent a major success for the policy - probably way beyond the government's or indeed anyone else's expectations.
'But it is early days and as the report itself acknowledges the analysis is not based on a fully representative sample of employers. The results cannot be applied to the whole population of employers particularly as medium and smaller employers will have different characteristics to larger employers, such as lower existing participation levels in workplace pensions.'