Related Rule
Australia
Practice Relating to Rule 145. Reprisals
Australia’s Commanders’ Guide (1994) defines a reprisal as “an act, otherwise unlawful under the international law regulating armed conflict, utilised for the purpose of coercing an adversary to stop violating the recognised rules of armed conflict”. 
Australia, Law of Armed Conflict, Commanders’ Guide, Australian Defence Force Publication, Operations Series, ADFP 37 Supplement 1 – Interim Edition, 7 March 1994, Glossary, p. xxiii.
The Guide further states:
Reprisals are otherwise illegal actions that are taken by one nation for the sole purpose of persuading another nation to comply with LOAC [law of armed conflict]. Nevertheless, because there is a risk that the conflict may escalate as a result, reprisals are rarely employed. 
Australia, Law of Armed Conflict, Commanders’ Guide, Australian Defence Force Publication, Operations Series, ADFP 37 Supplement 1 – Interim Edition, 7 March 1994, § 1211.
Australia’s Defence Force Manual (1994), in its table of definitions, defines the term “reprisal” as “an act, otherwise unlawful under the international law regulating armed conflict, utilised for the purpose of coercing an adversary to stop violating the recognised rules of armed conflict”. 
Australia, Manual on Law of Armed Conflict, Australian Defence Force Publication, Operations Series, ADFP 37 – Interim Edition, 1994, § 804.
The manual also states: “A reprisal is an otherwise illegal act done in response to a prior illegal act by the enemy. A reprisal aims to counter unlawful acts of warfare and to force the enemy to comply with the LOAC.” 
Australia, Manual on Law of Armed Conflict, Australian Defence Force Publication, Operations Series, ADFP 37 – Interim Edition, 1994, § 920.
The manual further states:
Reprisals are otherwise illegal actions that are taken by one nation for the sole purpose of persuading another nation to comply with the LOAC. Nevertheless, because there is a risk that the conflict may escalate as a result, reprisals are rarely employed. 
Australia, Manual on Law of Armed Conflict, Australian Defence Force Publication, Operations Series, ADFP 37 – Interim Edition, 1994, § 1310.
Australia’s LOAC Manual (2006) defines “reprisal” as: “An act, otherwise unlawful under the international law regulating armed conflict, utilised for the purpose of coercing an adversary to stop violating the recognised rules of armed conflict.” 
Australia, The Manual of the Law of Armed Conflict, Australian Defence Doctrine Publication 06.4, Australian Defence Headquarters, 11 May 2006, Glossary, p. 5.
The manual further states:
Nature of reprisals
13.17 Reprisals are acts which would normally be illegal, resorted to after the adverse party has itself carried out illegal acts and refused to desist when called upon to do so and issued with a warning that such action would be taken if the prior illegal act is not terminated. They are not retaliatory acts or simple acts of vengeance. Reprisals are, however, an extreme measure of coercion. Nevertheless, in the circumstances of armed conflict, reprisals, or the threat of reprisals, may sometimes provide the only practical means of inducing the adverse party to desist from its unlawful conduct.
Conditions for reprisal action
13.18 In order to qualify as a legitimate reprisal, an act must comply with the following conditions when employed:
• It must be in response to serious and manifestly unlawful acts, committed by an adverse government, its military commanders or combatants for whom the adversary is responsible.
• It must be for the purpose of compelling the adversary to observe the LOAC. Reprisals serve as an ultimate legal sanction or law enforcement mechanism. Thus, if one party to an armed conflict breaches the law but then expresses regret, declares that it will not be repeated and takes measures to punish those immediately responsible, then any action taken by another party in response to the original unlawful act cannot be justified as a reprisal.
• Reasonable notice must be given that reprisals will be taken. What degree of notice is required will depend upon the particular circumstances of the case.
• The victim of a violation must first exhaust other reasonable means of securing compliance before reprisals can be justified.
• A reprisal must be directed only against the personnel or property of an adversary.
• A reprisal must be in proportion to the original violation. Whilst a reprisal need not conform in kind to the act complained of, it may not significantly exceed the adverse party’s violation either in degree or effect. Effective but disproportionate acts cannot be justified as reprisals on the basis that only an excessive response will forestall further violations.
• It must be publicised. Since reprisals are undertaken to induce an adversary’s compliance with the LOAC any action taken as a reprisal must be announced as such and publicised so that the adversary is aware of the reason for the otherwise unlawful act and of its own obligation to abide by the law.
• As reprisals entail state responsibility, they must be authorised at the highest level of government.
• Reprisal action may not be taken or continued after the enemy has ceased to commit the conduct complained of. 
Australia, The Manual of the Law of Armed Conflict, Australian Defence Doctrine Publication 06.4, Australian Defence Headquarters, 11 May 2006, §§ 13.17–13.18; see also § 9.21.
The LOAC Manual (2006) replaces both the Defence Force Manual (1994) and the Commanders’ Guide (1994).
The Report on the Practice of Australia states: “Australia’s opinio juris is, with certain exceptions, supportive of a prohibition against belligerent reprisals.” 
Report on the Practice of Australia, 1998, Chapter 2.9.
Australia’s Defence Force Manual (1994) states: “Some nations may not comply with LOAC in the conduct of armed conflict. Where this occurs, and all methods of persuasion and diplomatic pressure have failed, reprisals may be justified but only against military objectives.” It adds: “In any case, reprisals must … only be resorted to after lesser forms of redress have been tried.” 
Australia, Manual on Law of Armed Conflict, Australian Defence Force Publication, Operations Series, ADFP 37 – Interim Edition, 1994, § 1310; see also Law of Armed Conflict, Commanders’ Guide, Australian Defence Force Publication, Operations Series, ADFP 37 Supplement 1 – Interim Edition, 7 March 1994, §§ 1210 and 1211.
Australia’s LOAC Manual (2006) states:
In order to qualify as a legitimate reprisal, an act must comply with the following conditions when employed … [including] … The victim of a violation must first exhaust other reasonable means of securing compliance before reprisals can be justified. 
Australia, The Manual of the Law of Armed Conflict, Australian Defence Doctrine Publication 06.4, Australian Defence Headquarters, 11 May 2006, § 13.18.
The LOAC Manual (2006) replaces both the Defence Force Manual (1994) and the Commanders’ Guide (1994).
The Report on the Practice of Australia states: “Australia’s opinio juris is, with certain exceptions, supportive of a prohibition against belligerent reprisals.” It adds, however: “Australian opinio juris does not consider that exceptions to the prohibition against reprisals, where these represent measures of last resort, will place it in breach of its customary obligations.” 
Report on the Practice of Australia, 1997, Chapter 2.9.
Australia’s Defence Force Manual (1994) and Commanders’ Guide (1994) state: “In any case, reprisals must be timely, responsive to the enemy’s conduct [and] proportional.” 
Australia, Manual on Law of Armed Conflict, Australian Defence Force Publication, Operations Series, ADFP 37 – Interim Edition, 1994, § 1310; Law of Armed Conflict, Commanders’ Guide, Australian Defence Force Publication, Operations Series, ADFP 37 Supplement 1 – Interim Edition, 7 March 1994, § 1211.
Australia’s LOAC Manual (2006) states:
In order to qualify as a legitimate reprisal, an act must comply with the following conditions when employed … [including] … A reprisal must be in proportion to the original violation. Whilst a reprisal need not conform in kind to the act complained of, it may not significantly exceed the adverse party’s violation either in degree or effect. Effective but disproportionate acts cannot be justified as reprisals on the basis that only an excessive response will forestall further violations. 
Australia, The Manual of the Law of Armed Conflict, Australian Defence Doctrine Publication 06.4, Australian Defence Headquarters, 11 May 2006, § 13.18.
The LOAC Manual (2006) replaces both the Defence Force Manual (1994) and the Commanders’ Guide (1994).
Australia’s Commanders’ Guide (1994) states: “Reprisal action by ADF [Australian Defence Force] members requires prior approval at the highest level.” 
Australia, Law of Armed Conflict, Commanders’ Guide, Australian Defence Force Publication, Operations Series, ADFP 37 Supplement 1 – Interim Edition, 7 March 1994, § 1211.
Australia’s Defence Force Manual (1994) provides: “Reprisal action by the ADF [Australian Defence Force] members requires prior approval at government level.” 
Australia, Manual on Law of Armed Conflict, Australian Defence Force Publication, Operations Series, ADFP 37 – Interim Edition, 1994, § 1310.
Australia’s LOAC Manual (2006) states: “In order to qualify as a legitimate reprisal, an act must comply with the following conditions when employed … [including] … As reprisals entail state responsibility, they must be authorised at the highest level of government.” 
Australia, The Manual of the Law of Armed Conflict, Australian Defence Doctrine Publication 06.4, Australian Defence Headquarters, 11 May 2006, § 13.18.
The LOAC Manual (2006) replaces both the Defence Force Manual (1994) and the Commanders’ Guide (1994).
Australia’s LOAC Manual (2006) states: “In order to qualify as a legitimate reprisal, an act must comply with the following conditions when employed … [including] … Reprisal action may not be taken or continued after the enemy has ceased to commit the conduct complained of.” 
Australia, The Manual of the Law of Armed Conflict, Australian Defence Doctrine Publication 06.4, Australian Defence Headquarters, 11 May 2006, § 13.18.
The LOAC Manual (2006) replaces both the Defence Force Manual (1994) and the Commanders’ Guide (1994).