The economic crisis is fuelling attacks on companies' information systems, with many firms worried that disgruntled former employees could retaliate by stealing or sabotaging data, a survey showed Wednesday.

The survey on 1,900 managers across 60 countries, carried out by accounting giant Ernst and Young, found that some 41 percent said that there has been an increase in attacks from outside their firms -- such as through phishing -- on their online information platforms.

A quarter also reported that amid the economic downturn, there has been an increase in attacks carried out within their organisations, such as the theft of data by employees or the abuse of access to information systems.

In fact, three-quarters of executives surveyed said they are concerned by possible reprisal from staff who had recently lost their employment.

"Our survey shows that the levels of internal and external risk continue to increase," said the report.

"To manage the increased risks, companies should develop a formal response aimed at dealing with employees likely to leave the organisation as a result of workforce reductions or job elimination," it added.

As a result, half of the respondents are planning to boost spending on securing their information systems, noted the survey.

Recent high profile cases of information theft include the sale of data of alleged tax dodgers stolen from a Swiss bank to German tax authorities.

The German case emerged just months after French authorities picked up a CR-ROM with raw data taken by a former employee of HSBC Private Bank in Geneva, Herve Falciani, allegedly with details on some 3,000 clients.

And in 2008, an anonymous whistleblower sold data on thousands of clients at Liechtenstein banks, helping Germany investigate suspected tax evasion by business executives, sports stars and entertainers.