The sponsor of the Institute of Financial Planning questioned almost 2,000 adults and found that the figure had doubled since the last survey was conducted in 2008.
Some 59 per cent of people said they would have to continue working either full-time or part-time after 65, up from 31 per cent in 2008.
The reasons given for staying in employment were that 69 per cent of employees needed extra money, 49 per cent wanted something interesting to do and 13 per cent wanted to give something back to society.

The report also found that 24 per cent of over-55s had failed to start saving anything for their retirement. Of those aged over 18 who had no retirement savings, 42 per cent said that they intended to start saving 'at some point' while 21 per cent said that they did not intend to save anything.
Mark Peters, head of retail propositions for Zurich UK Life, said: "Worryingly, although nearly two thirds of people have started saving towards their retirement, they are not saving enough to retire comfortably at 65.
"Given all the publicity about pensions – the state pension age increasing, the widely reported estimated £318bn pensions gap and the fact there may not be a state pension in the future – it seems people are still not recognising they need to save to ensure a financially secure retirement."