Latest figures from the Office for National Statistics show that there were more than 20,000 people in Devon and 12,000 in Cornwall still working after starting to collect their pensions at the end of 2011 – 13.4% of the total elderly population.
In Devon this represents a significant hike on the 9,000 recorded in 2002, and the 15,300 (10% of the over-65s) in 2010.
Cornwall has also seen a marked increase in the number of working pensioners rising from 6,700 (6.6%) in 2004 to 12,000 (10.4%) last year, although this is down from a high of 14,400 (12.6%) in 2010.
Plymouth recorded a hike over the period 2004-2011, from 1,400 to 2,800, as did Torbay from 1,800 to 2,800.
The Westcountry-wide increases comes against a background of economic turmoil, and rising food and energy bills.
Pensioners have also seen any additional income they receive from their savings plummet due to low interest rates.
Financial pressures are among the factors cited by the ONS to account for a rise nationally in more people working past retirement.
The fact that people are living longer and want to remain active has also contributed to the rise.
Tory MP for Newton Abbot Anne Marie Morris, who secured the figures for Devon in response to a parliamentary question, said: "It is interesting to see that the number of people aged over 65 in work has increased considerably in recent years. I think it is important for us to consider why because a balance does need to be struck between us benefiting from the wisdom the experienced provide in the workplace and the need for jobs to be available for our youngest generation."
Martyn Rogers, director of the charity Age UK Exeter, said: "As people are finding it harder to manage, with very low interests rates people aren't earning anything on their savings, it's not surprising people are choosing to work longer."
It comes as a peer suggested retired people could be encouraged to do community work such as caring for the "very old" or face losing some of their pension.
Lord Bichard, a former benefits chief who is a member of a committee investigating demographic changes and their impact on public services, said "imaginative" ideas were needed to meet the cost of an ageing society and stop older people being a "burden on the state".
The state pension age is already being increased by the Government to 67 for men and women by 2028, to reflect the fact that people are living longer. While saving money, the move will also generate extra cash from income tax and national insurance revenue as people work for longer.
The default retirement age in the UK was fully abolished last year, with employers prevented by law from compulsorily retiring workers once they reach the age of 65.
The Government recently announced pension changes aimed at ensuring people have enough cash in old age.
Against falling numbers of staff joining workplace pension schemes, the Government has introducing so-called "automatic enrolment", in a radical move to get people saving for their retirement.
Firms will have to sign up eligible employees to a pension, which they both will have to contribute into.
It has been hailed as they biggest shake-up in pensions for more than a century.
A spokesman for the Department for Work and Pensions said: "More of us are living longer. This means people are going to have to work beyond the traditional retirement age if they are to afford a good quality of life in retirement, and that's why the state pension age will rise over the coming years for men and for women.
"We are also helping to encourage more people to put something aside for the future, by automatically enrolling eligible people into a workplace pension."
