Related Rule
Australia
Practice Relating to Rule 155. Defence of Superior Orders
Australia’s Defence Force Manual (1994) provides:
ADF [Australian Defence Force] members are open to prosecution for breaches of LOAC. Individual responsibility for compliance cannot be avoided and ignorance is not a justifiable excuse. ADF members will be held to account for any unlawful action that leads to a serious breach of LOAC. If such acts are committed, compliance with unlawful orders of a superior officer is not a justifiable excuse. 
Australia, Manual on Law of Armed Conflict, Australian Defence Force Publication, Operations Series, ADFP 37 – Interim Edition, 1994, § 1306; see also Law of Armed Conflict, Commanders’ Guide, Australian Defence Force Publication, Operations Series, ADFP 37 Supplement 1 – Interim Edition, 7 March 1994, § 1207.
Australia’s LOAC Manual (2006) states:
13.7 ADF [Australian Defence Force] members are open to prosecution for breaches of LOAC. Individual responsibility for compliance cannot be avoided and ignorance is not a justifiable excuse. ADF members will be held to account for any unlawful action that leads to a serious breach of LOAC. If such acts are committed, compliance with unlawful orders of a superior officer is not a justifiable excuse …
13.42 The fact that a subordinate was ordered to do an act, or make an omission, which was illegal does not, of itself, absolve the subordinate from criminal responsibility. 
Australia, The Manual of the Law of Armed Conflict, Australian Defence Doctrine Publication 06.4, Australian Defence Headquarters, 11 May 2006, §§ 13.7 and 13.42.
The LOAC Manual (2006) replaces both the Defence Force Manual (1994) and the Commanders’ Guide (1994).
Australia’s War Crimes Act (1945), as amended in 2001, provides:
The fact that, in doing an act alleged to be an offence against this Act, a person acted under orders of his or her government or of a superior is not a defence in a proceeding for the offence, but may, if the person is convicted of the offence, be taken into account in determining the proper sentence. 
Australia, War Crimes Act, 1945, as amended in 2001, Section 16.
Australia’s Crimes (Torture) Act (1988), as amended to 2001, states:
11 No defence of exceptional circumstances or superior orders
It is not a defence in a proceeding for an offence against this Act that:
(a) the act constituting the offence was done out of necessity arising from the existence of a state of war, a threat of war, internal political instability, a public emergency or any other exceptional circumstance; or
(b) in doing the act constituting the offence the accused acted under orders of a superior officer or public authority;
but the circumstances referred to in paragraphs (a) and (b) may, if the accused is convicted of the offence, be taken into account in determining the proper sentence. 
Australia, Crimes (Torture) Act, 1988, as amended to 2001, § 11, pp. 5–6.
Australia’s Criminal Code Act (1995), as amended to 2007, states:
Defence of superior orders
(1) The fact that genocide or a crime against humanity has been committed by a person pursuant to an order of a Government or of a superior, whether military or civilian, does not relieve the person of criminal responsibility.
(2) Subject to subsection (3), the fact that a war crime has been committed by a person pursuant to an order of a Government or of a superior, whether military or civilian, does not relieve the person of criminal responsibility.
(3) It is a defence to a war crime that:
(a) the war crime was committed by a person pursuant to an order of a Government or of a superior, whether military or civilian; and
(b) the person was under a legal obligation to obey the order; and
(c) the person did not know that the order was unlawful; and
(d) the order was not manifestly unlawful.
Note: A defendant bears an evidential burden in establishing the elements in subsection (3). 
Australia, Criminal Code Act, 1995, as amended to 2007, Chapter 8, § 268.116, p. 380.
In 2003, in the SHCB case, the Federal Court of Australia noted: “The defence of obedience to higher orders will normally apply only where there are imminent real and inevitable threats to a subordinate’s life. There is an element of moral choice in relation to the defence …”. 
Australia, Federal Court, SHCB case, Judgment, 22 December 2003, § 31.
In 2005, in the SRYYY case, the Federal Court of Australia noted:
57 It is therefore difficult to discern a clear rule of customary international law with regard to the defence of superior orders …
77 Article 33 of the Rome Statute dealing with the defence of superior orders stands in a similar position [in being an appropriate definition for the Australian Administrative Appeals Tribunal to apply]. In providing for that defence in certain circumstances, albeit not for genocide or crimes against humanity, the article departs from the provisions made in previous instruments. While it may be an open question whether Art 33 accurately reflects customary international law, what is indisputable is that it reflects an international consensus in an international instrument that there is to be such a defence.
131 It is obvious that almost any offence can equally well be defined by including within its elements a negation of relevant defences, achieved in the case of murder by the use of the term “unlawful”, as by providing for separate and externally defined defences. In our view, there is no reason in principle for ignoring the possible availability of a defence of obedience to superior orders when determining whether there are serious reasons for believing that the person seeking refugee status has committed war crimes. 
Australia, Federal Court, SRYYY case, Judgment, 17 March 2005, §§ 57, 77 and 131.
In 2010, in the Habib case, the Full Court of Australia’s Federal Court unanimously held that the “act of state doctrine” did not bar a claim for damages based on the alleged complicity of Australian officials in the alleged acts of torture committed on the applicant by officials of the governments of the United States, Egypt and Pakistan. Black CJ stated:
[C]onsistently with Australia’s obligations under the [1984] Torture Convention, the parliament has spoken with clarity about the moral issues that may confront officials of governments, whether foreign or our own, and persons acting in an official capacity. It has proscribed torture in all circumstances, answering in the negative the moral and legal questions whether superior orders can absolve the torturer of individual criminal responsibility and whether, in extreme circumstances, torture may be permissible to prevent what may be apprehended as a larger wrong: see the Crimes (Torture) Act [1988], s 11; the Torture Convention, Art 2. 
Australia, Federal Court, Habib case, Judgment, 25 February 2010, § 10.
At the CDDH, Australia submitted an amendment concerning Article 77 of the draft Additional Protocol I which read: “In paragraph 2 delete the words ‘and that he had the possibility of refusing to obey the order’”. 
Australia, Amendment submitted to the CDDH concerning Article 77 of the draft Additional Protocol I, Official Records, Vol. III, CDDH/I/255, 24 March 1975, p. 331.
Later at the CDDH, Australia stated that it “supported the objectives sought in the ICRC text of article 77 [of the draft Additional Protocol I]”. 
Australia, Statement at the CDDH, Official Records, Vol. IX, CDDH/I/SR.51, 5 May 1976, p. 128, § 26.
With respect to its amendment submitted in 1975, it also stated that in this text “there was no provision which would give immunity to a soldier if he had had no opportunity of refusing to obey an order”. 
Australia, Statement at the CDDH, Official Records, Vol. IX, CDDH/I/SR.51, 5 May 1976, p. 128, § 28.