Workers in their thirties could be forced to continue in employment until they are more than 74 unless they dramatically increase the amount they save, according to a study by British insurance giant Prudential.
The organisation has said people in their thirties are setting aside an average of just £62 a month towards their retirement, some £340 a month less than they needed.
Its warning has come as a law firm has urged firms to review the way they treat older workers ahead of the new age discrimination laws that come into force later this year.
Law firm Brabers Chaffe Street warned that employers will have to do much better on areas such as recruitment, promotion, training, redundancy and retirement if they are not to fall foul of the new laws.
Evidence has also emerged of a widening gap between public and private sectors when it comes to pension provision, with figures showing that the number of final salary pension schemes in the public sector has overtaken those in the private sector for the first time in 30 years.
Taxpayers, it has been argued, will face a £690 billion bill to fund the pensions of public sector workers, the equivalent of a £300 hike in annual tax bills for every household over the next 30 years.
According to the UK government's Actuary's Department the number of public sector workers enrolled on final salary schemes has risen from 4.7 million to 5.5 million in the past five years, while the number of private sector workers enjoying the same benefit has fallen from 4.6 million to 3.6 million.
The Prudential's study warned that, to retire at 65 on two-thirds of pre-retirement income (including contributions from any state pension), a worker needed to be saving around £400 a month.
But if they were prepared to delay their retirement until 70, this dropped to £210 a month and if they waited to 74 current saving levels would need to go up by £50 a month.
Prudential predicted people in their twenties would have to delay retirement until they were 72 unless they changed their savings habits.
Debbie Falvey, head of retirement planning, said: "Today, many people approaching the end of their working lives take it for granted that they can stop working at 65.
"For the younger generation, as these figures show, stopping work at this age is increasingly likely to become a luxury unless they start saving more now," she added.