Elderly and disabled people who receive social care in their homes are "vulnerable to neglectful or abusive treatment" because of poor working conditions for care givers, a report has warned.
Care workers face a combination of inadequate pay, high pressure and a lack of support, the Equality and Human Rights Commission (EHRC) said.
The poor working conditions threaten the human rights of people in need of home care, it added.
While care workers conduct many tasks similar to nurses, their role is viewed as "lower status", a new report by the commission said.
The job requires "significant compassion and skill" and "maturity and resilience" yet their status does not reflect this, it adds.
The report states that the way care is currently run is "unsustainable" and called on local authorities to change the way home care is commissioned.
In particular, councils must ensure that workers - who are often recruited through external agencies - are paid the minimum wage, the EHRC said.
Many are not paid for travel time or the time between visits, which means that they could be working for less than the legal minimum wage, the report adds.
"We recognise the severe financial pressures local authorities are under, but unless commissioning practices change, the threats to older people's human rights will continue," the report states.
EHRC commissioner Sarah Veale said: "The current system of commissioning and funding home care is increasingly unsustainable as the number of people requiring care grows every year.
"Low status, low pay and poor working conditions are leading to high turnover of staff and putting older people's human rights at risk.
"Care workers perform a hugely valuable role in looking after some of the most vulnerable members of society and at the least should expect to be paid the legal minimum wage rather than being forced to fund transport costs and time spent between visits out of their own pockets.
"We recognise the extreme financial pressure local authorities are under. However, some authorities have taken innovative action in partnership with providers and older people to improve how they deliver care, without significant increases in expenditure."
Katie Hall, chairwoman of the Local Government Association's Community Wellbeing Board, said: "Helping people maintain their independence and dignity in old age is one of the most important things councils do and this report offers constructive feedback on the work local authorities are doing to improve a system that is widely recognised as being significantly underfunded.
"As the report acknowledges, the social care system is under enormous strain, with unprecedented cuts to council funding making it increasingly difficult to meet the escalating demand for care which is being caused by our aging population. While this means councils have to seek greater levels of efficiency, the quality of care remains the primary concern.
"Local authorities will not agree to contracts in which 15-minute visits are the basis for care. However, in some instances, such as administering medication, they may be appropriate as part of a comprehensive care plan that incorporates longer visits on a regular basis.
"Care providers do a vitally important job and deserve fair pay, which is why local authorities do not contract services at rates costed below minimum wage. Sustainable solutions around all aspects of pay and reward cannot be delivered in isolation from the other competing pressures on local government."
Heather Wakefield, head of local government at union Unison, said: "Local councils are suffering from dreadful cuts but this can never be an excuse for the kind of reckless commissioning that we continue to see in homecare.
"We know that more than 150,000 homecare workers are regularly paid below the national minimum wage and the EHRC has clearly demonstrated to councils that exploitative employment conditions for workers contribute to unsafe and humiliating care for clients.
"So it is a dereliction of duty for councils to commission homecare and pay no regard to whether providers are paying at least the legal minimum."
Caroline Abrahams, charity director for Age UK, said: "Funding pressures which result in tight visits often have a devastating effect on both the older people relying on these services as well as the staff forced to choose between rushing visits, leaving early without finishing tasks, or running late between clients.
"These sort of working conditions are unfair on the care workers themselves, increasing the risk of high staff turnover and little time off for training, resulting in an inexperienced and insufficiently-skilled workforce.
"Care providers, inspectors, and local authorities who arrange services must ensure that people's human rights are respected."
Care and Support Minister Norman Lamb said: "We want to create a fairer society where everyone receives better care and to achieve this we need a skilled and fairly-rewarded workforce.
"There are too many examples of employers paying people less than the minimum wage by not taking account of travel times, or of councils buying short care visits that leave people waiting to get into or out of bed, to eat and drink or take their medication.
"Social care organisations are independent and make their own decisions about their staff, but we are clear that they must abide by the law. We expect local authorities to commission good services that reward excellent care and pay fair wages.
"The newly-appointed chief inspector of adult social care will have an important role in holding councils to account where this is not the case."
It comes after a damning report revealed that the number of 15-minute care visits is on the rise.
Leonard Cheshire Disability estimated that the number of "flying" care visits has risen by 15% over the last five years.
Three quarters of local councils now commission some of their care in 15-minute slots.
The charity said that the short visits "simply do not allow enough time to deliver good-quality care".