The Pension Tracing Service is undergoing a major expansion, the Department for Work and Pensions announced.
The Newcastle-based body has 12 staff at the moment but this will rise to 49.
Jill Scott, operational manager at the Pension Tracing Service, said: "While it may sound strange, losing track of a pension is easily done, as people tend to move around the jobs market far more frequently than might have been the case in the past."

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The service was contacted a record 145,000 times last year, it reported, equating to double the number of enquiries in 2010.
Ms Scott said: "Independent research suggests that the most common reason for losing track of a pension is when an individual leaves an employer and does not keep them informed of any future changes of address.
"Estimates suggest that there could be as many as 50 million dormant and lost pension pots by 2050."
Minister for Pensions Steve Webb said: "With people having an average of 11 different jobs during the course of their working lives, it can be very easy to lose track of pensions they may have built up with previous employers.
"If you contributed to a pension in a previous job and don't have any details any more, it would be worth contacting our free PTS to see how you can be reunited with your lost pension pot.
"Whilst we have plans to help people combine their pension pots in future when they change jobs, there are still too many scattered and lost pensions, and we are working hard to make sure people get what they are entitled to."
From April the service will be complemented by the government's Pension Wise service, which will offer guidance to people over 55 about how they can make the most of the new pension freedoms once they take effect.
Around 300,000 individuals a year will be able to access their defined contribution pension savings, and Pension Wise is intended to be their first port of call.
It is expected that many customers will be referred to the PTS to track down lost cash.
In 87% of cases last year staff "successfully managed to put customers back in touch with their lost pension provider", the body reported.
Officials said 98% of enquiries from members of the public were dealt with in four days.