Indigenous public servants are quitting their jobs at almost twice the rate of non-indigenous colleagues and the bureaucracy's bosses do not know why.
Figures from the Australian Public Service Commission show the proportion of Aboriginal and Torres Strait Islander (ATSI) employees has been in steady decline in the service since 2002 and is now below the government's target of 2.7 per cent.
Public service authorities believe the problem is one of retention and say they are developing new ways to keep indigenous public servants in their jobs.
The commission said ''serious action'' is needed and has launched a four-year strategy aimed at attracting and retaining indigenous workers to federal government agencies.
Indigenous employment in the service was 2.3 per cent, or 3794 workers, in June last year, down from a high of 2.8 per cent in 2002.
The commission's latest bulletin, released with the 2012-2016 Indigenous Employment Strategy, is frank in its assessment.
''Serious action is required to increase the representation of indigenous employees in the APS,'' the bulletin says. ''This effort is needed to both recruit and retain indigenous employees in order to meet the government's 2.7 target.''
The commission says it is worried about the rate at which indigenous workers, particularly young staff, are walking away from the service.
The churn rate for ATSI bureaucrats is more than 12.3 per cent against a service-wide figure of 7.1 per cent.
''Not only are indigenous employees leaving at a greater rate, they are leaving earlier in their careers,'' the bulletin said. ''For example, in 2011-12 almost a third of all indigenous employees who separated had been with the APS for less than three years. This trend has continued for some years.''
More than 700 indigenous Australians have been hired by the APS since 2006 through the Pathways to Employment program, according to the commission, and if the strategy had not been established, ATSI representation might be as low as 1.9 per cent.
One of the commission's group managers, Owen Livermore, said work was under way to try to understand the high churn rate among indigenous public servants.
''A new thing is to roll out a survey and research with interviews to understand better why people are leaving,'' he said. ''There are a lot of theories, but they're not co-ordinated in terms of a reliable study.
''We're working on what we call cultural competency, that's making workplaces embrace diversity as much as possible and building that capability.
''It may sound soft, but it's actually a very important part of making the public service a good place for indigenous people to work.''
Mr Livermore said the APS Diversity Council, formed last year from the service's highest ranks, was working on ways for agencies to share expertise and success on indigenous representation.
''Some agencies like Human Service, FaHCSIA, DEEWR are doing better than the average and are expected to be because they are either regionally based or are in the game with indigenous policies,'' he said.
''But there are a lot of agencies that aren't doing so well so it's about being able to share practices and resources across the public service.''