The DWP's free Pension Tracing Service has helped 350,000 people find out if they are eligible for a workplace pension pot from previous employers.
The service, set up in 2005, helped one in five people who used it find a lost or forgotten pension pot.
This resulted in average weekly payments of £16 or an average lump sum of £1,900 that consumers did not know they had.
Last year, the service received 82,587 requests from investors confused about their small pension pots.
According to a DWP survey of people who used the service, 68% lost track of their pension because they moved to a new employer, whilst others forgot about their small pension pots when moving house, when their employers changed their names or closed down, or when they lost their paperwork.
"People need to make sure they are claiming everything they're entitled to in retirement," says pensions minister Steve Webb.
"If you think you may have had a pension in a previous job or you once paid into a personal scheme that you had forgotten about, the Pension Tracing Service may be able to help you to recover the money you invested."
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