More than 50 patients in the past year underwent surgery on the wrong part of their body as a result of NHS errors.

Despite government pledges that it should never happen, figures released yesterday by the National Patient Safety Agency (NPSA) revealed that 57 people in England went through "wrong site surgery" in 2009-10.

"Wrong site surgery" refers to an operation on the wrong limb or organ, or on the wrong person.

In total, there were 111 incidents of "never events" – things that should never happen in the NHS – over the 12-month period, including 41 incidents of misplaced feeding tubes in adults and children, something that puts patients at risk of being fed directly into the respiratory tract.

The Department of Health announced it was proposing an extension to the list of never events, taking it from eight to 22.

The expanded list will include medical instruments and swabs left in the body after surgery, the wrong route of administration of chemotherapy, death or injury resulting from the transfusion of the wrong blood type and death by falls from unrestricted windows in places such as mental health hospitals.

Hospitals can have funding withheld if a never event occurs.

The Health minister, Simon Burns, said "unsafe care is not to be tolerated", and warned that there will be "clear disincentives", including non-payment, for hospitals where such errors occur, as well as "clear incentives for quality".

"Across the NHS there must be a culture of patient safety above all else. These measures will help to protect patients and give commissioners the powers to take action if unacceptable mistakes happen."

Katherine Murphy, of the Patients Association, said: "The fact that a modern NHS has produced 111 never events is unacceptable.

"There should never be any cases where a doctor operates on the wrong limb or the wrong person.

"We welcome the news that the Department of Health is going to place more stringent controls on hospitals to ensure patient safety."