The National Employment Savings Trust (NEST) has backed calls to remove legal restrictions blocking it from taking transfers in and limiting contributions.
It said analysis of the impact of the restrictions on transfers and the contributions limit on both employers and members suggests there is a strong case for removing them by 2014.
The pension scheme said complexity and administrative burden on bosses and giving members more freedom were the two biggest reasons prompting the change.
NEST chief executive Tim Jones said: "NEST's restrictions complicate the decision-making process of medium-sized employers, many of whom will experience a private pensions sector already busy supporting other clients and who will therefore look to NEST as a potential provider.
"Removing the restrictions will help us help those employers to get the job done."
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