By Sarah Toyne BBC News Online personal finance reporter

The occupational pensions regulator, Opra, is warning trustees to be vigilant when transferring money between occupational pension schemes.

Opra is concerned that trustees are laying themselves open to complaints about so-called pension "liberation" schemes or "trust busters".

Up to 10 liberation schemes have appeared in the north west of England.

They promise to unlock the value of a company pension scheme before retirement, but the recipients lose up to 30% of the pension's value in commission.

Individuals could also find themselves in trouble with the Inland Revenue if they fail to declare money unlocked through the schemes, which are sometimes advertised as tax free.

Opra is urging trustees to implement better checks on company schemes and individuals who wish to transfer their pension, including demanding to see employment contracts and viewing two months' payslips, if suspicious.

Sales techniques

Under current rules, Opra can punish a trustee if they take longer than three months to make a pension transfer.

Trustee guidance

Ensure the scheme is registered with Inland Revenue's Savings, Pensions, Share Schemes office If it is not registered, check that it is a "valid unapproved scheme" Check with Companies House that the employer exists Ask for a contract of employment from the individual Ask for two months payslips

But Opra said it would relax that rule for companies which were concerned about a particular transfer - and urged them to take care and check a scheme's validity.

Sales commission

The schemes are being sold by door-to-door salesman, through advertisements and by word of mouth.

One report has indicated that people are being paid 1% commission to identify policy holders who may be interested.

The schemes are attractive to people who need ready cash, but participating could cost them dearly in the future.

They lose 20-30% in commission to the pension "liberator" and, if they fail to declare the cash, could be in trouble with the Inland Revenue.

The government is also concerned that policy holders unlocking pension benefits early could face an uncertain future.

The regulator has appointed independent trustees to look into three schemes - and the Inland Revenue is believed to be investigating up to seven.

Opra review

On Monday, the Department for Work and Pensions announced that it would be conducting a review into Opra.

As a non-departmental public body, Opra, which was established in 1997, must be investigated every five years.

Opra's functions and powers in the future will be moulded by a number of reviews into the pensions and savings industry which are being published in summer 2002.

An Opra spokesman welcomed the scrutiny.

"The fact that our review will coincide with the reviews is good as it means that the ideas can be put into the melting pot all at the same time," he said.

The National Audit Office is also looking into whether Opra is "value for money".