ANGRY taxpayers, welfare recipients and warring parents are using social media to vent their rage at public servants, triggering 1685 cyber-bullying complaints by federal bureaucrats.

And one-in-six federal public servants claimed to have been harrassed or bullied in one form or another in the past 12 months, data from the Australian Public Service Commission reveals.

The APC warns of an "emerging trend" of frustrated clients attacking public servants using social media such as Facebook and Twitter.

"In recent months the Commission has been approached by several (public service) agencies seeking advice in circumstances where employees have been the target of adverse comments by clients on social media websites," the APC says in its latest "State of the Service" report.

"In some of these cases employees were abused online by clients dissatisfied with their agency's services.

"However, the statements made tended to be of a highly personal nature."

The report notes that abuse on Twitter can have a "devastating impact" on the target.

One per cent of the 168,580 public servants said they had been cyber-bullied.

APC spokeswoman Clare Page said the commission did not have records of any compensation claims lodged for cyber-bullying.

She said public servants had the right to take private legal action for defamation.

But the Attorney-General's Department's legal guidelines prohibit paying the legal costs of public servants who want to sue for defamation.

The policy states that any funding of defamation proceedings "could give rise to a public perception that the Government was seeking to prevent legitimate criticism".

Community and Public Sector Union assistant national secretary Louise Persse warned that members of the public were "taking out their frustration on staff" over issues ranging from tax to child-support assessments, welfare payments and Medicare refunds.

Ms Persse called on the Federal Government to hire more staff, as cutbacks had created service delays in agencies including Centrelink and Medicare.

"Clients are taking out their frustration on staff because they are having to wait longer to be seen, or to get through to someone on the phone," she said.

"Putting more staff back on could help alleviate the rise in aggression."

Centrelink alone reported a record 5900 cases of "customer aggression" towards staff last financial year. Staff sounded duress alarms 951 times, according to data provided to a Senate estimates committee.

Taxpayers spent $2.8 million to post security guards in 63 Centrelink offices during 2011-12.

The APC report shows that 17 per cent of public servants - or 28,680 people - said they had been harrassed or bullied in some way, verbal abuse accounting for 55 per cent of complaints. Fellow public servants were chiefly to blame.

News Ltd revealed yesterday that compensation costs for stressed and injured public servants had doubled in a year to nearly $1 billion.

Comcare, the Commonwealth's workplace compensation insurer, has recorded its first loss, a startling $564 million for 2011/12.

Mental health claims made up 8 per cent of Comcare claims during 2011/12, and bullying accounted for nearly half of those.