Meantime, the DFAT official sacked over his alleged membership of a Facebook group was re-instated on Tuesday morning.

The minister has commented on the row over the Tweet sent by former Australian Taxation Office worker Darryl Adams in January 2012 about anti-porn campaigner Melinda Tankard-Reist.

Senator Abetz said Mr Adams’ departure from the tax office should act as a lesson for the nation’s 165,000 federal public servants and their use of Twitter and other social networking sites.

“The resignation of Darryl Adams from the tax office, who The Canberra Times today reported, was facing more punishment over his use of Twitter, underlines the need for public servants to exercise care when using social media,” the minister said.

“The reputation of the Australian Public Service will be enhanced by Mr Adams’ recognition of his need to resign, given his history of ill-advised Tweeting.”

The minister pointed out that the Public Service Commission had issued guidelines to bureaucrats about their online activities, advising public servants to think twice before hitting the send button.

“The guidance notes that APS employees need to ensure that they understand the APS Values and Code of Conduct and how they apply to the official and unofficial communications,” Sentaor Abetz’s statement said.

Mr Adams was punished and senior departmental officials apologised to Ms Tankard-Reist over the Tweet that Mr Adams sent from his “fake Paul Keating” account in January 2012.

Mr Adams Tweeted that Ms Tankard-Reist was "rootable in that religious feminist way", prompting the campaigner to make a formal complaint in June that year.

The public servant was sanctioned over the Tweet later in 2012 but the case came to life again in February 2013 after another complaint from Ms Tankard-Reist, this time about the handling of her original grievance.

More pressure was piled on the tax office in mid-2013 when the Ms Tankard-Reist complained to the Australian newspaper and the case was mentioned in a Senate estimates committee hearing.

In September, Mr Adams was found to have committed three breaches of the Public Service Code of Conduct and he resigned this month with further “sanctions” still hanging over his head.

Elsewhere in the service, Foreign Affairs officer Darrell Morris, who was sacked late last year over allegations he was behind Facebook threats to senior public servant in his department, has been given his job back.

Mr Morris was suspended in February 2012 and accused of being involved in the Facebook page called The Anti-Bullying and Discrimination League of Australia, an accusation he denies.

The page is one of many websites - such as Victims of CSIRO, APS Bullying and OzLoop - that have appeared in recent years and are dedicated to publishing claims of systematic bullying, harassment, cronyism and other wrongdoing in the public service.

DFAT bosses allege “the league” was responsible for sending defamatory and harassing emails to senior departmental officers and politicians.