Former pensions minister Sir Steve Webb is calling on the government to make partial defined benefit transfers a legal right.
The Royal London director of policy said the move would extend pension freedoms to a greater number of people.
Under current rules, members of DB schemes have a right to transfer the full cash value of their DB pension into a defined contribution scheme.
But while schemes are also allowed to offer partial transfers, most do not, as FTAdviser recently reported.
Sir Steve, who was pensions minister from 2010 to 2015, said lack of provision for partial transfers put long-term employees of single companies at a disadvantage.
Unlike people who have a number of DB pensions, he said those with a single pension were "faced with an all or nothing choice" between a guaranteed income and the flexibility of a DC pension.
"If I were an adviser, I would also sleep a lot better at night knowing my client still had a portion of their guaranteed income," he said.
A move to make it compulsory to offer partial transfers would likely be extremely popular with intermediaries.
FTAdviser recently spoke to a number of financial advisers about the issue, and all said they would like to see more schemes offering partial transfers, variously describing them as "extremely beneficial" and a "fantastic option".
But pension consultant Paul Darlow of Xafinity pointed out that partial transfers posed unique administrative difficulties - largely stemming from the fact that even in single schemes, members have "lots of little bits of pension" as a result of historical rule changes.
Addressing this difficulty, Sir Steve said: "I'm not saying they [schemes] should send out statements to every one of their members. It could be done on an at-request basis."
He said any move to make partial transfers a legal right would require legislation.
This process would have to be led by the Department for Work and Pensions, which has responsibility for trust-based pension schemes.
But HM Treasury would also need to be involved, because the Financial Conduct Authority, which reports to the Treasury rather than the DWP, regulates financial advice on DB transfers.
Sir Steve predicted the Treasury would be open to the idea because it would potentially mean greater tax revenue.
"If I were still a DWP minister, I would have thought I would get an open door from Treasury," he said.
Sir Steve said Royal London would be addressing the issue in its submission to DWP green paper on the DB sector, released last week.
The green paper focused on areas such as the indexation of benefits, the powers of The Pensions Regulator, and the need for scheme consolidation, but said very little about DB transfers.
When asked why it had given so little space to DB transfers, pensions minister Richard Harrington said it was not considered a "core subject". However, he said the subject might still be addressed in submissions.
james.fernyhough@ft.com
