This "results in a diminution of the 'space' in which the independent advisor can operate," he says.

He also suggests younger policy advisors are missing out on being properly mentored.

"Becoming an effective policy advisor requires 'learning by doing' under the guidance of experienced hands - an apprenticeship if you will.

"Today, in some institutions, smart people look around at their colleagues and find there is no one to talk to, to learn from, who has experience in delivering real reform.

Martin Parkinson is the new head of PM&C. Louie Douvis

"The combination of these two things is a decline in the quality of advice and an erosion of capability, to the detriment of good government," Dr Parkinson says in the essay.

Criticism by two of the nation's most respected and accomplished economic managers - with close to six decades experience in the federal bureaucracy between them - adds fuel to a growing debate about the broader value of long-standing public servants and their expertise.

Ms Tingle's Quarterly Essay - entitled Political amnesia: How We Forgot How to Govern - questions the cost of decades of outsourcing of political advice; the increasing politicisation of top posts; the tendency to continuously move leading mandarins between departments; as well as "periodic mass axing of public service heads upon the arrival of incoming conservative governments."


"The bureaucracy has been cowed both by the prospect of being sacked and by a reward system which punishes taking risks," Ms Tingle writes.

There are warnings in the essay that constant changes across the public service mean that "public servants don't necessarily stay on and live with the consequences of policy decisions."

The reappraisal of the public services comes after Australia swore in its fifth prime minister in as many years, underscoring a period of intense political instability that has coincided with increasing criticism about the quality of the bureaucracy and the advice it provides.

Yet cut-backs because of budget pressures may have eroded the public service's ability to provide good advice, Ms Tingle argues in the essay.

For instance, Dr Parkinson recalls being at the beginning of the tax reform debates of the 1980s and 1990s, when Treasury's expertise played a key role in the introduction of capital gains tax, fringe benefits tax, dividend imputation and, later, the introduction of the GST.

Thirty years later, Treasury now struggles to recruit people to its tax division. In addition, the Gillard and Abbott government's redundancy rounds have tended to hit older staff, many of them in the department's tax, or revenue group.

"Many of the older and more senior staff in this area were the last of those who had come through the ranks during the era of big change under Paul Keating and Peter Costello," Ms Tingle writes.

"Even as Treasury was being asked to prepare for a new round of tax reform - in conjunction with a group in Treasurer Joe Hockey's office - its tax division had a third less staff than it had three years earlier."

The Quarterly Essay notes that the median length of service of a public servant in mid-2014 was 9.4 years, which means only half the core workforce had a working life in the public service during the last few years of the Howard government.

"About half the public service doesn't remember the place working any differently to the way it has worked from the Howard era onwards – cannot recall a time when policy-makers in departments had a real role to play and there was a vital and active engagement with executive government," Ms Tingle writes.

"Ultimately, it is as though we as a community have ceased to recognise what a valuable repository of memory, and what a valuable institution, the public service is."