Up to 79 percent of the 156 Australian IT managers and C-level executives responding to a recent survey have suffered IT data breaches.

Some 40 percent of those have experience between six and 20 breaches over the last five years, and a further 59 percent claimed to have been hit with undetected data losses.

According to Symantec's Data Loss Prevention survey — which collected responses from local organisations with more than 100 employees and an annual turnover between $10 to $500 million — misplaced customer and employee records is the most common form of corporate data loss.

Intellectual property was lost in 43 percent of data breaches reported in the survey, followed by commercially sensitive information in 35 percent of cases, and lost bank and credit card data in 21 percent.

Staff are the biggest security threat, according to the figures. Human error was blamed in 42 percent of the reported cases of data loss, while 28 percent of losses were deliberately caused by staff.

Hackers were blamed for 29 percent of data breaches, while malware infections accounted for 24 percent.

The most expensive data breaches reported cost up to $1 million, while the average bill was less than $5000.