Managers could find themselves being disciplined if they fail to act against misconduct, the latest rulebook on wrongdoing in the Australian Public Service warns, and other time-honoured ways to avoid a fuss over bad workplace behaviour are no longer an option.

Simply allowing a culprit to quietly leave the department or the public service does not automatically mean the end of an investigation or punishment, according the Public Service Commissioner's newly published guidelines.

Sweeping a potential scandal under the carpet or dealing quietly with criminality "in-house" will become more difficult too, with clear-cut guidelines on when police should be called into investigate allegations against public servants.

The 2015 update to the public services's bad behaviour bible, Handling Misconduct: a human resource manager's guide, is much more comprehensive than its 2007 predecessor and leaves few excuses available to departmental bosses for failing to deal with their bad apples.

The commissioner's guide cites cases of public servants fraudulently using government-issued credit cards, cooking up allegations of assaults by their colleagues, storing and distributing pornography on departmental computers and running businesses on the side that made money from the bureaucrat's government day job.

The central message of the guide is that departments and agencies must have a clearly defined, well-understood process for every facet of its response to allegations of misconduct, cutting down on managers' discretion to take an ad-hoc approach, or no approach at all.

Managers in the public service have often been criticised for a reluctance to confront bad workplace behaviour or wrongdoing but have complained in turn of a lack of backing from departmental hierarchies for managers who call-out misconduct.

A traditional way of defusing potentially awkward situations has been to allow public servants facing allegations to quietly resign and 18 code of conduct investigations were discontinued in 2013-2014 because of the resignations of the alleged wrongdoer, down from 71 instances the previous year.

But in the commissioner's guidelines, managers were also reminded that rules have been on the books for nearly two years that allow public servants to be investigated and sanctioned even after they had moved to another department or left Commonwealth employment altogether.

The guidelines have a blunt warning for public servants who fail to report suspected breaches of their Code of Conduct.

"APS employees have a responsibility to report misconduct, and not to turn a blind eye to unacceptable behaviour," the guidelines state.

"Failure to report suspected misconduct may itself warrant consideration as a potential breach of the code."

Another frequent complaint from within the service is that rules are applied unevenly within and across departments.

While Public Service Commissioner John Lloyd made it clear, when publishing the new guidelines on Thursday, that each department and agency needed its own guidelines to reflect their different circumstances, fairness and consistency in enforcing the rules must be a guiding principle.

"Fair decisions ensure that APS employees and the community at large can have confidence in the fairness of our processes, and that decisions are well grounded and properly made," Mr Lloyd said.