Politically-motivated hacking incidents are on the rise, according to security researchers.

Paul Ferguson, advanced threats researcher at Trend Micro, said in a company blog that so-called 'hacktivist' attacks have become increasingly common and more dangerous in recent years.

"While most of the cyber-crime activities conducted on the internet are being driven by financial incentives, there also appears to be type of malicious activity being driven by other motivations altogether," Ferguson wrote.

The researcher noted the major attacks in Estonia last year, as well as a recent incident in which sites for Radio Free Europe were flooded with hits during coverage of a rally in Belarus for victims of the Chernobyl disaster.

Ferguson is not the only security expert to note such a trend. McAfee reported a similar rise in hacktivist activities last week following an attack on CNN by Chinese nationalist hackers.

The concept of hacktivism goes back more than 20 years, but a changing internet climate seems to be making the attacks more dangerous and effective.

"Incidents of hacktivism are not new, but they are beginning to become a lot more frequent," wrote Ferguson.

"This is perhaps due to the availability of tools, but also to the ubiquitous social networking mechanisms which can now be used to build consensus when times of cultural or political unrest present the opportunity."