Adult social care in England is in a "precarious state", MPs have warned.
The Public Accounts Committee (PAC) said the system is underfunded while the workforce is "suffering from low pay, low esteem and high turnover of staff".
MPs also raised concern over growing levels of unmet need.
The report comes as a leading health think tank, the Nuffield Trust, urged officials to look to Japan to learn lessons on how to solve the social care crisis.
The PAC report recognised the Department of Health and Social Care is "committed" to addressing the issues facing the sector through its workforce strategy and forthcoming green paper on funding of care for older adults.
But it added: "Given the pressures on the sector, we are concerned that the department sees the green paper as a cure-all and underestimates the scale of the challenge."
PAC chairwoman Meg Hillier (pictured) said: "Adult social care needs sustainable funding and a stable workforce.
"The sector is scraping by and without an explicit, long-term plan backed by Government it could soon be on its knees.
"Levels of unmet need are high and rising, short-term funding fixes are a road to nowhere and the ingrained issues that lead to high turnover in the workforce could be compounded by Brexit.
"We urge Government to publish this year, and then implement, a credible long-term funding plan for care.
"This must go hand-in-hand with financial and other support to improve the recruitment, development and retention of the care workforce."
The Nuffield Trust report concludes that the Government can learn important lessons from the Japanese system.
It says Japan's long-term care insurance system provides universal, comprehensive care to people over the age of 65 and those with a disability aged between 40 and 65.
The system is partly funded by a national insurance fund that all over-40s pay into and partly out of general and local taxation.
The Nuffield Trust said there are some elements of the Japanese system which can offer "important lessons" for the English system.
These include a national criteria for eligibility, meaning access to care is the same regardless of where a person lives; every three years the system is reviewed which gives the system flexibility; and people find the Japanese system easy to navigate as users are designated a "care manager" to help them get the help they need.
The Japanese system prioritises long-term prevention of loneliness and ill health, which contrasts with the English model, the authors added.
Natasha Curry, senior fellow in health policy at the Nuffield Trust, said: "As the Government begins to ask difficult questions about the future of social care, the Japanese experience in reforming long-term care for the elderly offers some important lessons for policymakers as they seek to bring about much-needed reform in England."
A Department of Health and Social Care spokeswoman said: "We know the social care system is under pressure - that's why we've provided an extra £2 billion funding to the sector and a further £150 million for the next year, and will shortly outline the Government's plans to reform social care to ensure it is sustainable for the future.
"We are also working on a joint health and social care workforce strategy to ensure the system is able to meet the demands of our growing ageing population as well as looking at ways to promote social care as a career of choice and attract staff to the profession."
Copyright (c) Press Association Ltd. 2018, All Rights Reserved. Picture (c) PA Wire.