A simple list to be checked off during surgery before anaesthesia, which includes knowing about patients allergy and counting surgical instruments has lowered the incidence of death and complications by one-third, a United Nations health agency said.

Studies undertaken in participating hospitals in each of the six World Health Organisation regions worldwide showed that the rate of major complications after undergoing surgery fell from 11 per cent in the baseline period to seven per cent, after introduction of the checklist.

"The concept of using a brief but comprehensive checklist is surprisingly new to us in surgery," said Atul Gawande, main author of the study and team leader for the development of the WHO surgical safety checklist.

"Not everyone on the operating teams was happy to try it. But the results were unprecedented. And the teams became strong supporters," he said.

Inpatient deaths following major operations fell by more than 40 per cent.

WHO says that 234 million major surgeries are now performed every year and that significant numbers of patients suffer or even die because of preventable complications.

Several studies have shown that in developing countries five to 10 per cent of patients die during major surgery.

Checklists include having knowledge about the patient's known allergies, surgical instruments, sponges and needles have to be counted to ensure that any avoidable complications does not take place.

Major complications are also reported in three to 16 per cent of patients in industrialised countries, while infections and other complications are also a serious threat.

The studies suggest that about half of these complications may be preventable.