Related Rule
New Zealand
Practice Relating to Rule 75. Riot Control Agents
New Zealand’s Military Manual (1992), in a footnote relating to the 1925 Geneva Gas Protocol, states: “A number of states, including New Zealand, take the view that this does not prevent the use of lachrymose agents, especially if used to maintain or restore discipline in internment or prisoner of war camps.” 
New Zealand, Interim Law of Armed Conflict Manual, DM 112, New Zealand Defence Force, Headquarters, Directorate of Legal Services, Wellington, November 1992, p. 5-15, § 512, footnote 51.
The manual further states: “Among other war crimes recognised by the customary law of armed conflict are … using asphyxiating poisonous and other gases.” 
New Zealand, Interim Law of Armed Conflict Manual, DM 112, New Zealand Defence Force, Headquarters, Directorate of Legal Services, Wellington, November 1992, § 1704(5).
New Zealand’s Chemical Weapons Act (1996) provides: “Every person commits an offence who intentionally or recklessly uses riot control agents as a method of warfare, and is liable on conviction on indictment to imprisonment for life or a fine not exceeding $1,000,000.” 
New Zealand, Chemical Weapons Act, 1996, Part II, Section 8.