A think tank has called for workplace pensions to be made compulsory in a bid to avert a savings crisis.
Policy Exchange said that a "help to save" scheme should be set up, which would remove people's ability to opt out of the workplace pension scheme they are placed in under.
Automatic enrolment into pensions was launched in autumn 2012. To date, a lower-than-expected rate of one in 10 employees are opting out once they have been placed into a pension scheme, but Policy Exchange said this level may rise as smaller firms are brought into the initiative.
The proposed "help to save" scheme would also see savers' contributions increase over time as their incomes rise.
Ideally, a 12% contribution rate should be targeted over the next five years rather than the 8% rate in operation, the report said.
The 8% rate is made up of 4% personal contributions, 3% company contributions and 1% from the Government in the form of a tax credit, but the report said that instead, the rate should be comprised of 6% from employees, 4.5% from companies and 1.5% from government.
The paper said that these measures would help to defuse a "pensions time bomb".
It said: "For those who argue that compulsion is not normal in the UK we would point out that tax, national insurance contributions and education are all compulsory.
"A failure to save sufficient funds for your retirement risks the state (and therefore other taxpayers) having to pick up the bill."
According to official estimates, the number of people aged over 65 is projected to increase from 17% of the UK population to 24% between 2012 and 2050.
The report warned that 11 million people are at risk of entering "pensioner poverty" when they retire. This is the number of people estimated to be facing inadequate retirement incomes.
The report said: "The gap between where we are and where we need to be is huge."
It suggested that someone earning the average wage of £27,000 would need to save over six and-a-half times more than they currently do to generate the Government's recommended retirement income of £16,200.
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The average pension pot is estimated to be just £36,800, which on current annuity rates is enough to generate a retirement income of £1,340. The paper said that an average earner would need a pot of £240,000.
James Barty, author of the report, said: "People are not saving enough for their retirement. This is putting an intolerable burden on the state which needs to be addressed sooner rather than later.
"With an ageing population, putting money aside for later life should be seen in the same context as national insurance contributions, taxes and even education - an obligation that falls on everyone in society."
Ros Altmann, an independent pensions expert and former government adviser, said action is needed to avoid increasing numbers of older people having to live on inadequate retirement incomes.
She said: "Ensuring that people contribute more than the auto-enrolment minimum is certainly important to deliver better pensions and using pay rises to fund higher contribution levels is the best approach."
