The survey results prompted the Ready for Ageing Alliance to say that action now was â€œcrucial for a happier old age for future generationsâ€.
The government insisted it had an ambitious programme for the elderly.
Some 76% of those polled also said they wanted a cabinet minister appointed to address the issue.
Jane Ashcroft, chief executive of Anchor, said: â€œWe ask government to prove to the public that they can future-proof policy. 137,000 people signed Anchorâ€™s petition for a minister for older people.
â€œGovernment cannot bury its head in the sand on the issue.â€
George McNamara, head of policy and public affairs at the Alzheimerâ€™s Society, added: â€œBy failing to prepare for the effect of an ageing population, we could be preparing to fail.
â€œWhile the government needs to plan for the impact of an ageing society, the public also needs to give more consideration to planning for their own old age.
â€œWe ignore the challenge of an ageing population at our peril.â€
The survey came as Office for National Statistics figures showed there were 12,320 people aged over 100 in England and Wales in 2012 compared with just 2,560 three decades ago.
The number of people aged over 90 has tripled over a similar time.
The government said changes to pensions and public services meant people would be able to save for retirement and get excellent care when they needed it.
A spokesman said: â€œWe want to make the UK one of the best places to grow old in and we have an ambitious programme to achieve this.
â€œWe are making radical changes to our pension system so people can plan and save for a decent income in retirement.
â€œWe are reforming our public services so that older people get excellent care and support when they need it and are enabled to live independently.
â€œIt is vital to make the most of the skills and talents that everyone has to offer.â€
The Ready for Ageing Alliance comprises eight charities consisting of Age UK, Alzheimerâ€™s Society, Anchor, Carers UK, Centre for Policy on Ageing, Independent Age, International Longevity Centre UK and Joseph Rowntree Foundation.