The department's annual report published on Tuesday shows an average of 16 days ''unscheduled absence'' for each full-time public servant in 2012-13, much of it in sick leave.

The absentee rate at DHS dwarfs the public service average of about 11 days a year and is approaching double that of private sector workers, who take just under nine days in unscheduled leave each year.

The mammoth department, which provides ''front-line'' services including Centrelink, Medicare and the Child Support Agency, lost an average of just under 15 days per public servant among its 36,000 workers in the previous reporting period, 11.2 of them to sickies.

It has not disclosed how many days of its workers' no-shows in 2012-13 were sick calls.

The growth in absenteeism comes despite a concerted effort from the department - and the broader public service - to get its employees to show up at work.

DHS bosses have come up with an ''attendance strategy'' that includes workshops and training courses for supervisors, to improve ''workforce availability'', according to the report.

''The department is committed to improving workforce availability through the implementation of an attendance strategy,'' the report says.

''This includes working with business areas to design and implement plans to reduce unscheduled absences, including conducting workshops with people teams and business unit managers about attendance and injury management and implementing a positive attendance training program for supervisors.''

Human Services identified in its report the biggest risk to its workers: ''body strain'', mostly caused by siting still all day at work, was responsible for 46 per cent of its workers' compensation cases, while mental stress caused more than a quarter of payouts. ''Customer aggression'' was also singled out as a key danger factor for DHS workers.

The department says it has implemented ''restricted service arrangements'' and ''customer management plans'' for members of the public who are likely to threaten or attack DHS public servants.

Supervisors have also been trained in supporting employees who have been the victims of threats or attacks at work.

The department says it is also working on its employees' psychological wellbeing, with managers being trained in ''mental health first aid'' and trials of suicide awareness training programs.

The public service's workplace authority, the Australian Public Service Commission keeps tabs on unscheduled leave in more than 100 departments and agencies where unscheduled leave can cost between 5 and 9 per cent of working days.

The commission sends out an annually updated guide, Turned up and Tuned in, to help public service managers get their staff to work.