More than two in five adults (41 per cent) do not know where their pension fund is invested, according to research from Baring Asset Management.
It said the large number - equivalent to eight million people in the UK - highlights a passive attitude towards saving for retirement and warned that people should adopt a more active approach through regular pension planning.
The survey also found that the number of adults who have never reviewed their pension plans is worryingly high - around 45 per cent or 16 million non-retired Brits.
"In spite of the on-going global financial crisis people are refusing to consider the impact it may be having on their long term savings," it said in a press release.
Personal or company pensions are most commonly paid via monthly or lump sum contributions to a pension provider, who will then invest it on the individual's behalf into a selection of investment funds; usually in fixed-interest bonds, property and shares.
However, it seems many are unaware that the choice of where to invest a pension fund often lies with the individual and will largely depend on their attitude towards risk and their investment objectives.
The same survey conducted in 2008, prior to the financial crisis, revealed that attitudes towards financial planning in 2012 have not improved, and in some cases worsened.
Elsewhere, a further 12 per cent could not remember when they last reviewed their pension, while under half had failed to review their pension plans in the last 12 months.
Marino Valensise, chief investment officer at Barings said that people were not taking the necessary action to ensure their pension provides what they will require in retirement.
"It is concerning to think that despite the very high profile global financial crisis that we are experiencing not more people have considered and acted upon the need to address how it may be affecting their funding in retirement."
"A large proportion is happy to accept the default setting which may not necessarily offer the best fit in terms of risk and reward. People who fail to take an interest in understanding the type of pension they have or indeed where it is invested are burying their heads in the sand."
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