Three areas of ethical conduct are at stake. One is the requirement for public servants to exercise impartiality and objectivity, not only in advice to ministers but also in any public statements, such as to Senate committees. As is generally recognised, public rationales for the policy towards boat people include considerable levels of hypocrisy and deceit. The real, unspoken reason for sending asylum seekers to Nauru, Papua New Guinea and now Cambodia is not to provide an alternative safe haven but to discourage future arrivals. For this reason, living conditions in these recipient countries must be sufficiently repellent pour dé´courager les autres, while offering a plausible, but minimal, fig leaf of humane protection. Public servants called on to answer questions about conditions in the detention centres are compelled to connive in these known fictions out of loyalty to their ministers.

Certainly, ministers themselves carry most of the burden of public justification. Indeed, the level of government hypocrisy has receded somewhat with the incoming Coalition government and its ruthless Immigration Minister, Morrison. We hear less of Labor's mealy-mouthed excuses of stopping the ''vile trade'' of the people smugglers or of saving lives at sea (except when Morrison is cornered in debate). The aim is now clearly to stop the boats and stem the tide of unwanted asylum seekers. Even so, the deliberate, state-sanctioned victimisation of asylum seekers is an evil that dare not speak its name. The Immigration Department's public servants are forced to maintain the charade that their main concern is the detainees' interests. Such prevarication is hardly consistent with an ethical commitment to objective and impartial communication.

A second value compromised by asylum-seeker policy is the public service's commitment to accountability. For example, the government's refusal to allow public servants or military officers to answer questions on ''on-water'' matters marks a major restriction on normal understandings of official accountability. In the recently revised Public Service Act, accountability is elevated to one of the five core values, presumably to mark its bedrock importance in public service ethics.

Admittedly, the principle of public service accountability is significantly qualified in the act, which says ''the APS is open and accountable to the Australian community under the law and within the framework of ministerial responsibility'' (my emphasis). However, this caveat, as explained in the Public Service Commission's guidelines, refers primarily to public servants' obligation to avoid commenting on matters of government policy and to refrain from expressing partisan opinions. Within these limits, the guidelines say, public servants should provide Parliament "with full and accurate information about the factual and technical background to policies and their administration''.

The guidelines recommend that where questions are likely to be ''politically sensitive'' public servants ''should consult beforehand with the minister's office'' and allow the minister to have the final say on what information is revealed. Morrison may therefore have legal authority to gag his officials on what are clearly matters of administration, not policy. But his official rationale - to avoid alerting the people smugglers - rings hollow. The more the people-smugglers and their intended clients know about government treatments of boat people, surely, the more likely they are to be deterred. The real reason for the media blackout is to avoid domestic accountability. (Ironically, Kevin Rudd, before the last election, also co-opted people smugglers as cover for domestically focused media policy on boat people. But, on that occasion, the policy called for maximum publicity about the new harsh arrangements, not secrecy.)

On any reasonable assessment, the minister's gag on officials asked for information about on-water operational matters is an unwarranted restriction on Parliament's rights to hold the government to account. For example, the Senate committee on foreign affairs, defence and trade, when questioning the heads of the Immigration Department and Customs and the military commander of Operation Sovereign Borders, has met with outrageous stonewalling, sometimes of ludicrous, Gilbertian dimensions. These senior officials are being obliged not only to make themselves appear foolish but also to repudiate their normal professional standards. Their refusal to answer even the most mundane factual questions relating to on-water operations may be technically within the terms of the Public Service Act's injunction for public service accountability ''within the framework of ministerial responsibility''. But it is clearly contrary to the spirit of the act.

A third area in which immigration officials may be compromising their professional values relates to the general, overriding injunction at the heart of public service ethics: that all public servants' actions should be within the law. A professional, rule-based and law-abiding bureaucracy, alongside an independent judiciary and an honest police force, is an essential element in the rule of law. Any bureaucratic behaviour that strays outside the law's strict parameters must be considered a threat to the integrity of government.

The legality of current asylum-seeker policy is a question of fierce public controversy and what the law demands is not always clear. For example, refugee advocates reject strongly the government's description of boat people as ''illegal arrivals'' on the ground that asylum seekers, however they may have gained entry, have not broken any Australian law. In response, Morrison has argued, correctly, that the term ''illegal entry'' is used in the UN refugee convention to refer to asylum seekers who have entered a country without legal permission. However, the convention goes on to say that illegal entrants seeking asylum should not be penalised for that reason. When the minister and his officials use ''illegal arrivals'' to imply that boat people are less legitimate than other asylum speakers, they clearly distort the correct legal position.

Refugee advocates argue regularly that asylum-seeker policy and those administering it are breaching Australia's international legal obligations. Strictly speaking, however, public servants' actions only become illegal if they contravene Australian law, including those aspects of the UN refugee convention that are incorporated into Australian legislation such as the Migration Act.

Two recent instances suggest the government may well have breached Australian law. One involves the policy of offshore settlement for boat people found to be refugees, which was introduced by the 2013 Rudd government and continued by the Coalition. Recent amendments to the Migration Act allowed for the offshore processing of asylum-seekers in designated overseas countries. But they did not explicitly envisage the major new step of permanent settlement in those countries, an extension of the policy that was introduced without explicit parliamentary or legislative authority.

The second instance involves the seizure of the 153 Sri Lankan asylum seekers en route from India, a case that is before the High Court. Whatever their eventual legality, the actions of government officials - first in holding the asylum seekers incommunicado at sea for weeks and then spiriting them out of the country overnight - hardly suggest a government keen to comply with the rule of law. Rather, they reflect a government that seeks to frustrate vulnerable individuals' legal rights, an approach that has characterised Australian asylum-seeker policy for many years, even decades. Public servants caught up in implementing this policy are being asked to engage in legally questionable activities.

Public servants are not personally responsible for compromising their professional values in this way. They are acting under the direction of elected ministers who are themselves reflecting widespread public attitudes. The root cause is that the law's requirements are out of step with the consensus of political opinion as reinforced by the electorate in successive elections. In effect, both main parties, with public backing, have committed themselves to a de facto rejection of the UN refugee convention insofar as it applies to those who arrive without legal permission. The Migration Act, however, still reflects the convention's broad intent. Government hypocrisy and deceit, on both sides of politics, follow from this fundamental clash between democratically endorsed policy objectives and the law - a contradiction that undermines the rule of law.

To date, few advocates of the rule of law within the legal profession are pressing for this anomaly to be rectified by bringing the law into alignment with government policy. Presumably, they still cling to the empty hope that future governments will change the current policy and reopen the borders to boat people in accordance with the existing law. Others, perhaps, are ashamed that Australia should need to modify its legal support of the UN refugee convention at a time other countries around the world are facing refugee problems that dwarf this country's.

In the meantime, government ministers continue to preside over a yawning gap between their legal commitments and their actual practice. Public servants, who have a professional duty to follow ministers' directions while upholding principles of objectivity, accountability and the rule of law, find themselves the meat in this constitutionally unsavoury sandwich.

Richard Mulgan is an emeritus professor at the Crawford School of Public Policy at the Australian National University. richard.mulgan@anu.edu.au