The Pension Schemes Bill has received Royal Assent to become official legislation ahead of freedom and choice taking effect from 6 April.
Giving savers rights to probe pension funds on specific details of investments would be an "undue burden" on schemes, according to the National Association of Pension Funds (NAPF).
Lord German has called for pension scheme trustees to account to members for "all actions taken in the performance of their investment functions".
Proposals to give savers the right to request information on their schemes will rebuild trust in the pensions industry, according to a think tank.
A proposed change to the Pension Schemes Bill would put an end to non-disclosure agreements (NDAs) that hide the fees that schemes pay asset managers.