Cuts are putting care under "stress and strain" and carers' efforts are being undermined, the chief inspector of adult social care in England has said.
Andrea Sutcliffe told the Observer many carers ended up being "the sort of care worker you wouldn't want them to be".
There were 30,000 allegations of abuse of people using social care services in the first six months of this year, according to the newspaper.
The Department of Health said it was determined to "stamp out" abuse.
Adult social care budgets have been cut by £4.6bn since 2010 - a 31% overall reduction - according to the Association of Directors of Adult Social Services. The association estimated in June that councils were facing a £1.1bn shortfall this year.
Ms Sutcliffe, a chief inspector at health and social care watchdog the Care Quality Commission (CQC), said funding cuts had led to carers feeling overworked and under-valued, undermining the work they do.
She told The Observer: "That potentially means that they may leave, and we do see turnover, but it also may mean that they end up being the sort of care worker that you wouldn't want them to be because the system around them isn't supportive.
"The social care sector is certainly under stress and strain. And that is a combination of all sorts of factors - the increased numbers of people who need care and support, the increased complexity of their needs."
Meanwhile, a Freedom of Information request by the Observer suggested there were 30,000 allegations of abuse involving people using social care services in the first six months of 2015.
Allegations ranged from physical, emotional and sexual abuse, to financial fraud.
The rate at which allegations of abuse have been made doubled between 2011 and 2015, the newspaper reported.
In more than half (57%) of allegations in care homes it was a professional carer who was the alleged abuser, according to an analysis of 2013-14 figures.
Across the social care sector - including cases of abuse in people's own homes - professional carers were identified as the abuser in a third of cases.
BBC cost of care project
A Department of Health spokesman said that while an increase in awareness and reporting of abuse was to be welcomed, abuse and neglect were "completely unacceptable at all times".
He said: "Treating someone with dignity and compassion doesn't cost anything.
"We're making sure we recruit people with the right values and skills by introducing a 'fit and proper person' test for directors and a care certificate for front-line staff.
"The CQC's new tougher inspection regime will also help to make sure that if abuse does occur, it's caught quickly and dealt with."
'Health and wellbeing'
Separately, figures released by the Carers Trust suggested the UK's six million carers were struggling to take holidays. They said 68% had not been able to go away on a break this year, with a third saying they had not even had a full day off to themselves.
Chloe Wright, policy manager at carers' rights charity Carers UK, told BBC Radio 5 live it was "so important to get that break for your good health and wellbeing".
She said many carers did not take breaks as they do not know what help they were entitled to, and that some struggled to find replacement care, with the lack of funding in social care budgets exacerbating the situation.
"We know many carers are struggling financially," she added. "More than half say they struggle to make ends meet.
Ms Wright added that carers were twice as likely to be in poor health than non-carers, "often because they don't have the time to look after themselves and get to appointments".