Almost one in four people scheduled to retire this year say they are not ready to stop work, according to a report.
A survey of more than 1,000 people nearing retirement found that one in seven had already delayed their plans.
A wider poll of around 7,000 adults found that just over half would consider working beyond the state pension age because of financial considerations.
Prudential said its study also revealed that many people wanted to carry on working to keep mentally and physically fit.
Stan Russell of Prudential said: "For many people retirement is now a gradual process rather than a watershed where you simply stop working one day and become retired the next, and that is reflected in the change in attitudes shown by our research.
"Working past traditional retirement ages is not solely driven by financial pressures and the research shows growing numbers of people wanting to carry on working because they enjoy it and because it keeps them stimulated mentally and physically.
"Increased life expectancy and improvements in general health are changing how we think about retirement."