Related Rule
Australia
Practice Relating to Rule 37. Open Towns and Non-Defended Localities
Australia’s Defence Force Manual (1994) states:
727. A non-defended locality is any inhabited or uninhabited place near or in a zone where opposing armed forces are in contact and which has been declared by parties to the conflict as open for occupation by a party to the conflict. In order to be considered a non-defended locality, the following conditions must be fulfilled:
(a) all combatants, weapons and military equipment must have been evacuated or neutralised;
(b) no hostile use is made of fixed military installations or establishments;
(c) no acts of hostility are to be committed by the authorities or the population; and
(d) no activities in support of military operations shall be undertaken.
728. The presence in this locality of protected persons and police forces retained for the sole purpose of maintaining law and order, does not change the character of a non-defended locality.
729. A non-defended locality may be declared by a party to the conflict. That declaration must describe the geographical limits of the locality and be addressed to the relevant party to the conflict which must acknowledge its receipt and from that time treat the locality as a non-defended locality unless the conditions for establishment of the locality are not met. 
Australia, Manual on Law of Armed Conflict, Australian Defence Force Publication, Operations Series, ADFP 37 – Interim Edition, 1994, §§ 727–729; see also Law of Armed Conflict, Commanders’ Guide, Australian Defence Force Publication, Operations Series, ADFP 37 Supplement 1 – Interim Edition, 7 March 1994, § 921.
Australia’s LOAC Manual (2006) states:
7.29 The parties to the conflict may declare as a non-defended locality any inhabited or uninhabited place near or in a zone where armed forces are in contact which is open for occupation by an adverse party. In order to be considered a non-defended locality, the following conditions must be fulfilled:
• all combatants, weapons and military equipment, must have been evacuated or neutralised;
• no hostile use is made of fixed military installations or establishments;
• no acts of hostility are to be committed by the authorities or the population; and
• no activities in support of military operations shall be undertaken.
7.30 The presence in this locality of protected persons and police forces retained for the sole purpose of maintaining law and order, does not change the character of a non-defended locality.
7.31 The declaration of a non-defended locality must describe the geographical limits of the locality and be addressed to the relevant party to the conflict which must acknowledge its receipt and from that time treat the locality as a non-defended locality unless the conditions for establishment of the locality are not met. In that case, the locality continues to enjoy the protection provided by other provisions of Additional Protocol I and other rules of international law applicable in armed conflict.
7.32 The parties to the conflict may also agree to grant the status of a non-defended locality to a particular area even if the conditions referred to in paragraph 7.29 are not fulfilled. Although there is no specific format or content for any such agreement, the principal points should be:
• the exact geographical limits of the area;
• the date and time of entry into force;
• the duration;
• the rules on marking the limits of the area and the type of marking to be used;
• persons or classes of persons authorised to enter the locality;
• if necessary, the methods of supervision; and
• the ultimate fate of the locality and the possible conditions under which the area may be occupied by enemy troops.
7.33 Non-defended localities are to be signposted and although the status may be lost when the conditions upon which it was established are no longer being satisfied, the locality shall continue to enjoy any other protection afforded by the LOAC.
7.34 Even though all the conditions are not met, the parties may agree between themselves to treat an area as a non-defended locality. The agreement should be in writing and should specify the exact geographical limits of the locality, the date and time of the entry into force of the agreement and its duration, rules on marking the locality and agreed signs, persons authorised to enter the locality, methods of supervision (if any), whether and under what conditions the locality may be occupied by enemy troops. 
Australia, The Manual of the Law of Armed Conflict, Australian Defence Doctrine Publication 06.4, Australian Defence Headquarters, 11 May 2006, §§ 7.29–7.34; see also § 9.40.
The LOAC Manual (2006) replaces both the Defence Force Manual (1994) and the Commanders’ Guide (1994).
Australia’s Defence Force Manual (1994) states: “Towns, villages, dwellings or buildings which are undefended are also protected from attack.” 
Australia, Manual on Law of Armed Conflict, Australian Defence Force Publication, Operations Series, ADFP 37 – Interim Edition, 1994, § 534; see also § 732 (siege warfare).
With respect to non-defended localities, the manual states:
Military objectives within a non-defended locality, from which hostile acts are being conducted, can be attacked, subject to weapon and targeting considerations … Otherwise, non-defended localities cannot be attacked. 
Australia, Manual on Law of Armed Conflict, Australian Defence Force Publication, Operations Series, ADFP 37 – Interim Edition, 1994, §§ 726 and 732.
The manual further provides that “making non-defended localities … the object of attack” constitutes a grave breach or a serious war crime likely to warrant institution of criminal proceedings. 
Australia, Manual on Law of Armed Conflict, Australian Defence Force Publication, Operations Series, ADFP 37 – Interim Edition, 1994, § 1315(k); see also Law of Armed Conflict, Commanders’ Guide, Australian Defence Force Publication, Operations Series, ADFP 37 Supplement 1 – Interim Edition, 7 March 1994, § 1305(k).
Australia’s LOAC Manual (2006) states:
5.37 Towns, villages, dwellings or buildings which are undefended are also protected from attack …
Undefended localities
7.27 The attack or bombardment, by whatever means, of towns, villages, dwellings, or buildings which are undefended is prohibited. The reason for this rule is that there is no military need to attack a place that is not being defended. It can simply be occupied without resistance or bypassed. The concept of an undefended place does not apply to places in rear areas behind enemy lines. It applies only to places that are open to occupation by ground forces.
Non-defended locality
7.28 It is prohibited for parties to a conflict to attack, by any means whatsoever, non-defended localities.
Siege warfare
7.35 Attack on towns, villages, habitations or buildings that are undefended is prohibited unless they have become military objectives. 
Australia, The Manual of the Law of Armed Conflict, Australian Defence Doctrine Publication 06.4, Australian Defence Headquarters, 11 May 2006, §§ 5.37, 7.27, 7.28 and 7.35; see also §§ 9.24 and 9.43.
The manual also states:
[The 1977 Additional Protocol I] extends the definition of grave breaches to include the following … acts when committed wilfully, in violation of the relevant provisions of the protocol, and causing death or serious injury to body or health:
• making non-defended localities … the object of attack. 
Australia, The Manual of the Law of Armed Conflict, Australian Defence Doctrine Publication 06.4, Australian Defence Headquarters, 11 May 2006, § 13.26.
The LOAC Manual (2006) replaces both the Defence Force Manual (1994) and the Commanders’ Guide (1994).
Australia’s War Crimes Act (1945) considers “any war crime within the meaning of the instrument of appointment of the Board of Inquiry [set up to investigate war crimes committed by enemy subjects]” as a war crime, including the deliberate bombardment of undefended places. 
Australia, War Crimes Act, 1945, Section 3.
Australia’s Geneva Conventions Act (1957), as amended in 2002, provides: “A person who, in Australia or elsewhere, commits a grave breach … of [the 1977 Additional Protocol I] is guilty of an indictable offence.” 
Australia, Geneva Conventions Act, 1957, as amended in 2002, Section 7(1).
The grave breaches provisions in this Act were removed in 2002 and incorporated into the Criminal Code Act 1995.
Australia’s Criminal Code Act (1995), as amended to 2007, states with respect to serious war crimes that are committed in the course of an international armed conflict:
268.39 War crimeattacking undefended places
A person (the perpetrator) commits an offence if:
(a) the perpetrator attacks or bombards one or more towns, villages, dwellings or buildings; and
(b) the towns, villages, dwellings or buildings are open for unresisted occupation; and
(c) the towns, villages, dwellings or buildings do not constitute military objectives; and
(d) the perpetrator’s conduct takes place in the context of, and is associated with, an international armed conflict.
Penalty: Imprisonment for life.  
Australia, Criminal Code Act, 1995, as amended to 2007, Chapter 8, § 268.39, p. 328.
The Criminal Code Act states with respect to war crimes that are grave breaches of the 1977 Additional Protocol I:
268.98 War crimeattacking undefended places or demilitarized zones
A person (the perpetrator) commits an offence if:
(a) the perpetrator attacks one or more towns, villages, dwellings, buildings or demilitarized zones; and
(b) the towns, villages, dwellings or buildings are open for unresisted occupation; and
(c) the attack results in death or serious injury to body or health; and
(d) the perpetrator’s conduct takes place in the context of, and is associated with, an international armed conflict.
Penalty: Imprisonment for life. 
Australia, Criminal Code Act, 1995, as amended to 2007, Chapter 8, § 268.98, p. 371.
Australia’s ICC (Consequential Amendments) Act (2002) incorporates in the Criminal Code the war crimes defined in the 1998 ICC Statute, including “attacking undefended places” in international armed conflicts. 
Australia, ICC (Consequential Amendments) Act, 2002, Schedule 1, § 268.39; see also § 268.98 (grave breach of the 1977 Additional Protocol I).