More than 4,300 whistleblowers have come forward in the past 16 months to complain about the treatment of elderly and disabled people in care.
The Care Quality Commission (CQC) - which regulates care homes and hospitals in England - said some of the complaints concerned care home residents being physically assaulted.
Complaints rose from 22 a month in December 2010 to 556 in March 2012.
The CQC said whistleblowers included relatives and staff.
The commission said that among the issues raised were members of staff assaulting residents, refusing to take residents to the toilet, shouting at elderly and disabled patients and failing to respond to call bells.
There were also complaints about levels of staffing.
Amanda Sherlock, from the CQC, said the increase was partly linked to greater awareness following a BBC Panorama programme which exposed the abuse of patients at Winterbourne View private hospital near Bristol.
Chris Skidmore, a Conservative MP on the House of Commons Health Committee, obtained the information about the rise in complaints using a Freedom of Information request.
He told the Times newspaper the figures were "alarming... suggesting that beneath the surface the scandal of poor quality care is still highly relevant."
Gary FitzGerald, chief executive of Action on Elder Abuse, told the Times low-level incidents could develop into serious abuse.
He said even walking into a resident's room before knocking could escalate: "Next it may be not closing the door when someone is on the toilet."
Mr FitzGerald claimed politicians had failed to stop the decline in standards of dignity for the elderly: "Labour started this degradation and the coalition has simply made it worse."