Related Rule
New Zealand
Practice Relating to Rule 145. Reprisals
New Zealand’s Military Manual (1992) states:
A reprisal is an illegal act resorted to after the adverse Party has himself indulged in illegal acts and refused to desist from them after being called upon to do so. The reprisal is not a retaliatory act or simple act of vengeance. 
New Zealand, Interim Law of Armed Conflict Manual, DM 112, New Zealand Defence Force, Headquarters, Directorate of Legal Services, Wellington, November 1992, § 1606(1).
The manual further states:
In order to be considered a reprisal, an act must have certain characteristics:
a) It must respond to grave and manifestly unlawful acts committed by an adverse government, its military commanders, or combatants for whom the adversary is responsible.
b) It must be for the purpose of compelling the adverse Party to observe the law of armed conflict. Reprisals cannot be undertaken for the law of armed revenge, spite or punishment. Rather, they are directed against an adverse Party in order to induce him to refrain from further violations of the law of armed conflict. Thus, reprisals serve as an ultimate legal sanction or law enforcement mechanism. Above all, they are justifiable only to force an adverse Party to stop its illegal activity. If, for example, one Party to an armed conflict commits a breach of law but follows that violation with an expression of regret and promise that it will not be repeated, and even takes steps to punish those immediately responsible, the other Party cannot justify a lawful reprisal as the appropriate action to “right” the situation.
c) There must be reasonable notice that reprisals will be taken. What degree of notice is required will depend on the particular circumstances of each case. Notice is normally given after the violation but may, in appropriate circumstances, predate the violation. An example of notice is an appeal to the transgressor to cease its offending conduct and punish those responsible. Thus, such an appeal may serve both as a plea for compliance and a notice to the adverse Party that reprisals will be undertaken.
g) It must be publicized. Since reprisals are undertaken to induce an adverse Party’s compliance with the recognized rules of armed conflict, any action taken as a reprisal must be announced as a reprisal and publicized so that the adverse Party is aware of its obligation to abide by the law. 
New Zealand, Interim Law of Armed Conflict Manual, DM 112, New Zealand Defence Force, Headquarters, Directorate of Legal Services, Wellington, November 1992, § 1606(4).
New Zealand’s Military Manual (1992) states:
(c) There must be reasonable notice that reprisals will be taken. What degree of notice is required will depend on the particular circumstances of each case. Notice is normally given after the violation but may, in appropriate circumstances, predate the violation. An example of notice is an appeal to the transgressor to cease its offending conduct and punish those responsible. Thus, such an appeal may serve both as a plea for compliance and a notice to the adverse Party that reprisals will be undertaken.
(d) The victim of a violation must first exhaust other reasonable means of securing compliance in order to justify taking reprisal. 
New Zealand, Interim Law of Armed Conflict Manual, DM 112, New Zealand Defence Force, Headquarters, Directorate of Legal Services, Wellington, November 1992, § 1606(4)(c) and (d).
New Zealand’s Military Manual (1992) states:
[The reprisal] must be proportionate to the original wrongdoing … The proportionality is not strict: if the reprisal is to be effective, it will often be greater than the original wrongdoing. Nevertheless, there must be a reasonable relationship between the original wrong and the reprisal measure. 
New Zealand, Interim Law of Armed Conflict Manual, DM 112, New Zealand Defence Force, Headquarters, Directorate of Legal Services, Wellington, November 1992, § 1606(1).
The manual further states:
In order to be considered a reprisal, an act must have certain characteristics: … A reprisal must be proportional to the original violation. Although a reprisal need not conform in kind to the same type of acts complained of (bombardment for bombardment, weapon for weapon) it may not significantly exceed the adverse Party’s violation either in violence or in effect. Effective but disproportionate reprisals cannot be justified by the argument that only an excessive response will forestall further transgressions. 
New Zealand, Interim Law of Armed Conflict Manual, DM 112, New Zealand Defence Force, Headquarters, Directorate of Legal Services, Wellington, November 1992, § 1606(4)(f).
New Zealand’s Military Manual (1992) states: “In order to be considered a reprisal, an act must have certain characteristics: … It must be authorized by national authorities at the highest political level and involve full State responsibility.” 
New Zealand, Interim Law of Armed Conflict Manual, DM 112, New Zealand Defence Force, Headquarters, Directorate of Legal Services, Wellington, November 1992, § 1606(4)(h).
New Zealand’s Military Manual (1992) states: “A reprisal … must be terminated as soon as the original wrongdoer ceases his illegal actions.” 
New Zealand, Interim Law of Armed Conflict Manual, DM 112, New Zealand Defence Force, Headquarters, Directorate of Legal Services, Wellington, November 1992, § 1606(1).