Workers are being warned to think twice before using Facebook and Twitter after a survey revealed a rising number of workplace disciplinary hearings in Leeds.
Hundreds of staff at councils, hospitals and schools have been investigated and in some cases sacked for misusing the internet at work.
Many got in trouble for using social networking sites and for posting abusive messages while others resigned or were dismissed for viewing pornography or sending racist material.
A survey by the Yorkshire Post has revealed that teachers, social workers and firefighters were among those caught in the net.
Employment lawyers say that private companies are facing similar problems with staff.
Cases uncovered using the Freedom of Information Act, covering the last five years include 158 Wakefield Council staff being investigated for misusing electronic equipment, two of which were sacked.
Nine cases were investigated in Leeds with two staff members being sacked, one for looking at porn.
And four West Yorkshire fire service staff received warnings for sending offensive material.
Public sector organisations have claimed only a small proportion of staff are ignoring the rules.
Euan Lawrence, solicitor in employment law at Blacks solicitors in Leeds, believes that the misuse of social media is increasing.
“We deal with lots of clients who have had cases of employees misusing the internet at work. We’ve recently assisted employers which have had to deal with employees bringing the employer into disrepute through postings on Twitter or Facebook, sending inappropriate emails to colleagues and customers and viewing pornographic content on their work computer.
“Some employees don’t think twice about sending flirtatious messages internally at work or posting statuses about how much they hate their job. However, these are just some examples of online activity which has resulted in disciplinary hearings or, in certain cases, dismissals.”