Just one quarter of people think they will receive the social service care they need in old age or if they suffer disability, according to new research.
A poll commissioned by 75 charities and voluntary organisations found that only 27% of people in England believe there would enough help available for themselves or a family member.
It concluded that concerns over care could prove crucial at the general election, with voters ranking the issue second only to health as a government spending priority.
Asked about how the coalition is dealing with care, more than half of respondents (55%) said the Government should be doing more.
Richard Hawkes, chairman of the Care and Support Alliance (CSA), said: "Care is well and truly an election issue.
"The message from the public is loud and unambiguous. It's a real vote of no confidence.
"They are worried about who will care for them or their loved ones, if they can no longer do basic things for themselves.
"Above all, they want the Government to invest more money in the system."
T he YouGov poll of almost 4,700 people in England for the Care and Support Alliance found that a third of the population (32%) rely on the care system either for themselves or a close family member.
Asked what public services the Government should spend more on, 67% of respondents replied h ospitals and local GP surgeries, followed by 47% who said more money should go towards s upporting for elderly and disabled people.
As respondents got older, they expressed increasing concern over the care that would be available to them and their loved ones.
Some 39% of people in their late teens and early twenties believed they would not receive adequate care compared to two thirds (71%) of those over 60.
An upcoming overhaul of the care system will see its cost capped for the first time.
But the CSA said that the system was "on its knees", suffering from a surge in demand and "chronic under-funding", with fewer people getting the attention they need.
And it pointed to claims made last month by councils that £3.5 billion has come out of the care system in the last four years.
Research by the London School of Economics has shown that 500,000 people who would have got care in 2009 are no longer entitled to it.
The findings announced today come ahead of the publication next week of a report on the future shape of England's care system.
A panel of experts led by economist Kate Barker and backed by the King's Fund health think tank will set out a blueprint for merging parts of the social care system with the NHS.
Experts have warned that integration of the two systems is required to cope with the demands placed on them by an ageing population.