As many as 6,000 savers may be tempted by the Government's new retirement freedoms to make the irrational decision to transfer out of their "gold plated" pension, according to a scenario published by the City regulator.

The Financial Conduct Authority (FCA) is consulting on planned new rules which will require people with a defined benefit (DB) pension who are considering transferring out of it to take advice to make sure they fully understand what they are giving up.

From April 6, people aged 55 and over with a defined contribution (DC) pension will be handed new freedom and choice over the way they access their money, enabling them to take their pot all in one go or in a series of slices. They will be able to spend their money as they wish, rather than being herded towards buying a retirement income called an annuity.

The new freedoms will not apply to holders of DB pensions. These types of pension are often described as "gold plated" because unlike DC schemes, they promise pension savers a certain, guaranteed level of income in their retirement, such as final salary pensions or career average pensions.

The number of DB schemes which are still open to savers has shrunk back in recent years as firms have found them increasingly expensive to run, as people live for longer.

But despite the benefits they offer, as the new pension freedoms come into force, the FCA expects that more DB scheme members will seek to transfer their benefits to DC schemes to have early and more flexible access to their pension savings.

In many cases, transferring from a DB to a DC pension may not be in the member's best interests, it said, although there may be a limited number of circumstances where a valid case for transferring can be made, such as where a consumer has limited life expectancy.

In its consultation document, the FCA said it does not have a credible way of determining the scale of the number of "irrational" consumers.

But it built a scenario whereby an extra 3,000 to 6,000 potential transfers could take place due to consumers behaving irrationally, "which, if they took place, might lead to material consumer detriment".

To protect consumers who might otherwise lose valuable DB benefits, the Government is introducing a requirement that individual scheme members take advice from an adviser authorised by the FCA before a transfer is allowed to proceed.

The new regime will bring advice on transfers from DB schemes to occupational defined contribution DC schemes into the FCA's remit.

Consumers will be required to take advice before transferring out of a DB scheme and it will be the responsibility of trustees to check that people have taken advice.

The FCA will also require those advising on pension transfers to have a pension transfer specialist qualification when giving advice on all transfers from DB to DC schemes regardless of when the transferred benefits are being accessed.

Christopher Woolard, director of strategy and competition at the FCA said: " DB schemes pose particular issues and we need to ensure that those who are considering moving away to other arrangements are fully aware of the potential benefits they are giving up.

"In many cases transferring from DB to DC may not be in the member's best interests and ensuring independent advice is taken is an important protection."

Responses to the consultation will be taken until April 15 and the updated rules will be in place for June.

Richard Eagling, head of pensions at financial information website Moneyfacts.co.uk, said: "The new pension freedoms will doubtless encourage many individuals in defined benefit schemes to consider the merits of transferring to a defined contribution pension arrangement.

"However, the FCA has made it clear that advisers will need to tread very carefully when dealing with this and it is still perceived to be the case that in most scenarios remaining in a defined benefit scheme will be the most suitable choice in the long term."