Rule changes to give more people access to Self Invested Personal Pensions (SIPPS) are setting the scene for unscrupulous and unregulated companies to take advantage, consumer watchdog Which? claims.

Workers with existing occupational pensions schemes will be able to invest in SIPPS for the first time from the 6th April. Current SIPP holders will also be able to extend their investments into residential property.

SIPPS is likely to grow in popularity as investors get tax relief for assets that they put into their pensions. So for every pound a higher tax rate payer puts into their pension, the government will in turn give 40 pence.

But SIPPS remain unregulated which could leave consumers in the lurch if things go wrong.

Many unknown property companies have also sprung up which focus on the tax breaks offered by the government but provide sketchy details about the retirement packages they actually offer.

Which? pension specialist Mick McAteer says this leaves customers vulnerable to money making scams.

"It's like watching a car crash happen in slow motion and being unable to do anything to stop it. All the conditions are there for mis-selling. There is a need for a bit of a public awareness campaign on this," he said.

David Baker, a director of Britain's largest SIPP provider, James Hay, a wholly owned subsidiary of Abbey, agreed.

"It's a very dangerous area. The biggest area of concern is residential property," he said.

"We've been contacted by between 50 and 70 companies in the last year wanting to sell their products to our SIPP clients and most of these we haven't heard of," he added.