Almost 100 organisations have reported data security breaches in the six months since HM Revenue & Customs lost information relating to 25 million child benefit records.
Information Commissioner Richard Thomas said that there have been 62 reported breaches within the public sector, 28 in the private sector and four at voluntary and charitable bodies.
Thomas described the figures as "alarming" and urged leaders in the public and private sectors to make data protection a priority.
"It is particularly disappointing that the HMRC breach has not prevented other unacceptable security breaches from occurring," he said.
"The government, banks and other organisations need to regain the public's trust by being far more careful with people's personal information."
Reported breaches included the loss and theft of unencrypted laptops, computer discs, memory sticks and paper records containing financial and medical data.
The Information Commissioner's Office has requested that offending organisations make procedural changes in 16 cases, as just three cases resulted in the recovery of lost data.
Thomas insisted that more must be done to eradicate "inexcusable security breaches", and that new requirements for Whitehall departments and guidance for the public sector would be put in place to help address the issue.
The timing of the Commissioner's findings coincide with the publication of a PricewaterhouseCoopers survey indicating that more than three-quarters of respondents had reported thefts of unencrypted laptops.
More than one in 10 respondents to the Information Security Breaches Survey had also detected the presence of unauthorised outsiders within their network.
