The actions of former employees are posing an increasing risk to companies, according to a new study.

Researchers from Ernst & Young said in the firm's annual Global Information Security Survey that as more companies are forced to cut staff, information theft and destruction at the hands of former workers is becoming an increasing risk.

"With the economy still in recession, employees who are made redundant may feel resentful towards their previous employer in a number of ways that may affect the smooth operation of an organisation," said Ernst & Young IT risk advisory partner Richard Brown.

"Increasingly, the employer’s IT system has become a common target and data theft is also prevalent."

Further complicating matters are the budgetary constraints being placed on IT departments as a result of the economic crisis. As the risk from security threats increases, IT managers are being forced to provide tighter security with less money.

The study found that 52 per cent of companies surveyed said that they would not be able to increase spending on information security.

Adding to the pressure on security budgets are new regulations that bring additional compliance costs, the study found. Some 55 per cent of firms surveyed said their compliance costs had increased.

"Information security today already requires a lot more investment, as organisations race to catch up with an accelerating threat landscape, after a much delayed start," said Brown.

"However, information security is not immune to external economic forces and senior IT professionals will need to improve efficiency and effectiveness while keeping spending to a minimum."