Many older and disabled people will be shut out of vital services under the Government's plans for reform of the care system in England, charities have warned.
Care providers also claim the proposals risk pushing GP surgeries and Accident & Emergency departments to breaking point.
The Care Act, which passed into law last month, will be the most comprehensive overhaul of the system since 1948, providing the first-ever national eligibility threshold - a set of criteria determining when local authorities will have to provide people with support.
Reforms also include a personal cap on personal care costs of £72,000, excluding accommodation, and councils will have a new duty to provide preventative services.
Launching a consultation on the draft regulations and guidance for the first part of the Act, Care and Support Minister Norman Lamb said putting people in control of their care and limiting the amount anyone may have to pay for the support they need would make the system fairer.
But the measures have been widely criticised by age and health charities as well as companies providing care services.
Caroline Abrahams, charity director at Age UK, said the new regulations were "not good enough", claiming people with dementia who need help to continue to live at home with dignity could be "screened out", as well as those who struggle with day-to-day tasks such as dressing, washing, going to the toilet or preparing food.
She praised the Government for standardising the system, but criticised the criteria as "far too restrictive".
"From now on the inability to do just one of these fundamental things will not be enough to qualify you for support and Age UK's concern is that without it, some older people's needs will escalate, undermining their capacity to continue to live at home," she said.
Mencap chief executive Jan Tregelles said the charity had long called for a national system of eligibility to "end the postcode lottery" dictating who can and cannot have access to social care, but insisted the Government had set the bar too high.
She added: "The Government shuts out thousands of people with a learning disability from getting the support they desperately need. Many people who need help with the day-to-day tasks like managing money, medication and being supported to be part of their community may no longer get it.
"We know the huge difference support can make to people's lives, and how devastating the consequences when they don't get it - needs can quickly escalate, pushing people and families to crisis point."
Home Group, one of the UK's largest providers of social care services, called for an "urgent amendment" to the rules to allow those with "moderate" as well as "substantial" needs to access support. Otherwise it warned the Government would be faced with a "care crisis" as people turned to A&Es for help.
RachaeI Byrne, its executive director of care and support, said: "Many people who have relied on care from their local council will find themselves squeezed out...t his will place an intolerable strain on an already overstretched NHS.
"The social care system is on its knees...The Government must be bold and go further than it plans."
Richard Hawkes, chairman of the Care and Support Alliance, a coalition of 75 organisations, accused the Government of "passing up" the chance to drive through a " genuinely preventative system".
He added: "It has instead hard wired the year-on-year rationing that's seen people squeezed out."
The consultation is open until August 15 and centres on the changes that will come into effect from April 2015.
A further consultation on the reforms that come into effect from April 2016 - which include the cap on care costs - will take place this autumn.
Simon Bottery, director of policy at the charity Independent Age, said while some aspects of the regulations were welcome, such as those protecting people against unfair top-ups, some aspects were "deeply troubling".
He called the requirement for older people to demonstrate that being unable to wash or dress themselves had an effect on their well-being "scarcely believable".
"The Department of Health has made a serious error here that will have to be addressed as part of the consultation," he added.
Richard Kramer, deputy chief executive at national deaf blind charity Sense, agreed the bar had been set "far too high" in terms of eligibility for social care.
He added: "It is also vital the Government releases enough funds for local authorities to provide the right level of support for what is currently a chronically underfunded system. Otherwise the Care Act will be built on sand."
Paul Farmer, chief executive of mental health charity Mind, said taking away a "very low level of relatively inexpensive support " would risk people becoming very unwell.
"You risk people reaching crisis point where they feel suicidal or are harming themselves, at which point they will need much more intensive and expensive hospital or home-based health care," he continued.
"As our NHS mental health services strain at the seams and struggle to cope with the numbers of people in crisis, the Government would be well-advised to consider the long-term implications of denying thousands of people the basic support they need.
"A little initial investment in social care will not only save money in the long run - it will save lives."