And the Public Service Commission's new five-point plan to get public servants showing up for their jobs says "engagement" is the key to a workforce that wants to turn up.

The commission has turned its attention to the "hot topic" of "attendance management" in the federal public service as one large department battles for the right to insist on sick notes when its bureaucrats do not show up.

The Agriculture Department, one of the few federal outfits where workers do not have to supply medical evidence for no-shows, wants its 4000 public servants to vote this month for a new workplace agreement that would allow managers to ask for medical certificates after three days absence.

The Commonwealth's largest department, Human Services, is clashing with its main workplace union over the department's tactic of putting serial absentees on "attendance plans".

Now the Public Service Commission has launched its updated "absence management toolkit" for departmental managers, with the commission noting that "absence management is a hot topic across the APS."

The overall no-show rate across the public service improved slightly in the 2015-2016 financial year, to 11.5 days per year for each employee on average, after years of getting worse.

But attendance at large agencies like Agriculture and Human Services remains a problem, with an average annual no-show rate of two-and-half weeks.

Comparisons with the private sector are difficult but the commission cites research from the Australian Human Resources Institute that puts the average private sector figure at 7.4 days per year and the not-for-profit sector at 9.8 days per year.

But the commission's research shows 68 per cent of unscheduled absence across the Commonwealth public service is supported by a medical certificate.

The research also showed that a lot of unscheduled leave was being taken by a small number of public servants.

"This includes a large amount of leave taken by a relatively small group of employees," the commission wrote.

But there is hope, the commission says, with the employee census offering a way forward by creating workplaces where employees want to show up.

"The data also identifies a complex, but clear relationship between employee engagement and absence," the commission advised,

"The 2016 APS Employee Census data suggests that employees with higher engagement levels take fewer days of sick and carer's leave.

"This is supported by industry research that provides links between an engaged workforce and its impact on unscheduled absence."

The commission is also calling on the public service's army of middle-managers to step-up and be "strong leaders" who improve the culture of their departments.

"Agencies are able to influence employee engagement by developing strong leaders, effective workplace operations and by offering some degree of autonomy in the workplace," the attendance guide reads.

"Good attendance and productive performance is fundamental to workforce capacity.

"It needs to be addressed in a systemic way, with everyone on board.

"Managers also have significant impact on the culture of an agency."