The role of customary law in Papua New Guinea's legal system

Papua New Guinea's (PNG) legal system is one that has intertwined common, customary, and statutory law. Unique to PNG, customary law must be considered before the common law in almost all cases. The three sources of law in PNG are 'written law' (section 9 of the PNG Constitution) and common law (section 3(1) of the Underlying Law Act 2000), with a unifying, though ambiguously defined, foundation of customary law. Customary law finds its best expression in statute.

These complexities become particularly evident in sectors such as mining and petroleum , where disputes over land ownership, resource rights, and benefit distribution often pit customary landowners against state control and corporate interests, highlighting the tensions within PNG's legal framework.

Customary Law in the legal system

The legal system of Papua New Guinea is based on the English common law overlaid with comprehensive national legislation. This system provides for the integration of the ‘Kastim Lo’ (generally customs, language, and rules for each group) from across over 800 distinct tribal jurisdictions. Each jurisdiction has its own language and rules. The language which unites the groups is ‘Tok Pisin’ – a dialect derived from German, English and local Kastim. In practice, PNG laws are written in English, with a court system operating primarily in English.

Before separation from being an Australian Territory in 1975, custom was recognised in several statutes including the Marriage Act, Land Titles Act and Local Courts Act, however it received its first real platform of recognition as an important part of the legal system through its inclusion in the Constitution in 1975. Prior to the constitutional ratification, the drafters created the report for the National Goals and Directives Principles (NGDP).

In the preamble to the Constitution, it states inter alia in the 5th goal of the National Goals and Directives Principles that: “custom is to play a role and have a place in the lives of PNG in the modern world, because custom has always had a place in governing people’s lives such as resolving disputes, participation in ceremonies and the like.”

The legislative schema is primarily derived from the Constitution, the Customs Recognition Act 1963 and the Underlying Law Act 2000. Section 9 of the Constitution provides a list of the hierarchy of laws. It starts with the Constitution as the supreme law and ends with the Underlying Law. Moreover, Schedule 2.1.8 of the Constitution provides that custom is one of the sources of the Underlying law, along with the common law.

For custom to be a source and applied as part of the Underlying Law, it must satisfy certain conditions, called the repugnancy test (Schedule 2.1.1). Schedule 2.1.2 says custom can be applied provided it is not inconsistent with the Constitution or a statute or repugnant to the general principles of humanity. The purpose of Schedule 2 and any act of Parliament created by Constitution section 20, is for custom to be a source of and assist in the development of PNG’s indigenous jurisprudence.

The Customs Recognition Act provides guidance on how customary law is recognised and applied in criminal and civil cases. Subsection 5(1) states that customary law can be recognised, enforced, and used in all courts, provided that doing so is in the public interest. However, if the case involves a child under 16, the court must ensure that applying customary law is in the best interest of the child

The Underlying Law Act is another example of custom’s recognition and status in PNG’s legal system. Its creation is to be founded in Schedule 1.2 and Section 20 of the Constitution. Section 3 of the ULA states customary law and common law are sources of the underlying law. Section 4 states customary law and common law can be adopted as part of the underlying law.

Together, the CRA and the ULA, underwritten by the Constitution, provide customary law is to be applied in favor of the common law.

Application of customary law 

Subsections 4(2) and (3) of the ULA set out the conditions for which customary law can be applied. For instance, if its application is not inconsistent with written laws, then it would not be contrary to the NGDP and Basic Social Obligations.

Where a court refuses to apply customary law must give reasons for the refusal to do so, by how the customary pleading failed to meet the conditions under 4(2) and (3). It allows that custom, prescribed under the CRA, may be considered in civil cases in order to establish the ownership by custom or rights over, in or in connection with customary land or anything on or in customary land, or the produce of land including hunting or gathering rights.

Also, if a court applies common law over customary law, it must likewise give reasons for doing so. In the fundamental constitutional case of Re Petition of Michael Thomas Somare [1981] PNGLR 265, the court said a court must positively decide a custom is inapplicable before considering the common law.

If a matter arises before the court where a question of two or more customs are pleaded to apply, such that there is a conflict in the substance of the law or if there is a conflict on the applicability of each customary law, the court may adopt the system the court is satisfied would satisfy the justice of the case requires.

Mining and petroleum compensation

As Papua New Guinea's legal system has continued to evolve, the application of customary law in matters of land ownership and resource extraction has become increasingly important.

The ownership of mineral and petroleum resources in Papua New Guinea has been a contentious issue, with significant legal and socio-economic implications emerging prominently since the late 1980s. The crux of this controversy revolves around whether these resources belong to the state or to customary landowners who hold traditional rights to the land on which these resources are extracted.

This debate encompasses broader struggles over the distribution of financial benefits from large-scale mining and petroleum projects, involving various stakeholders including the state, mining and petroleum companies, landowning groups, and finally the national and provincial governments.

The legal framework governing mineral ownership in PNG has evolved from historical precedents. The Mining Act 1977 is the primary legislation that regulates mineral ownership and consolidates earlier laws, namely the Papua Mining Ordinance 1928 and the New Guinea Mining Ordinance 1938. Both of these earlier ordinances, modeled after Australian mining laws, vested ownership of all minerals in the state. The Mining Act largely retained this provision, continuing the thread of state claim over mineral resources. Latent potential for oil production, meant that petroleum was contemporaneously recognised in PNG by the Petroleum Act 1977.

Two main legal issues have arisen in applying customary ownership in mineral and petroleum ownership claims. First, whether customary landowners retain rights beneath their land or whether such rights were extinguished The second issue is whether the legislation constitutes an unconstitutional deprivation of property without compensation, given that the Constitution protects property rights. The resolution of these issues hinges on whether the legislation, which predates the Constitution, is saved by its historical context or whether it conflicts with the constitutional protections for property rights.

The legal landscape shifted significantly with PNG's independence in 1975, when the new Constitution recognized the importance of customary laws alongside existing legal frameworks. This tension between customary landownership and state control over mineral resources became increasingly prominent toward the end of the 1980s and into the 1990s, and early 2000s. The growing discontent over the distribution of benefits from mining and petroleum projects triggered a legal and political struggle.

Two notable cases simplify the struggle: Donigi v The Independent State of PNG (Originating Summons No. 207 of 1990) and Paterson Lowa and Others v Wapula Akipe and Others (Supreme Court Appeal 19, 32, 36 and 60 of 1991).

In Donigi, the plaintiffs challenged state ownership of minerals, but the court dismissed the case on the grounds that the applicants lacked standing, thereby avoiding a substantive examination of the ownership issue (Donigi v The Independent State of PNG, unreported). This procedural dismissal prevented a detailed judicial review of the contention that customary landowners should hold rights to minerals beneath their land.

The Paterson Lowa case involved a challenge to Conzinc Rio Tinto's lease rights to the Mt. Kare Gold Mine. Initial disputes over preliminary rulings by the National Court led to appeals, and the Supreme Court directed that the case be remitted back to the National Court for trial. Given the constitutional questions at stake, it is anticipated that the National Court may ultimately refer these matters back to the Supreme Court (Paterson Lowa and Others v Wapula Akipe and Others, unreported). As it stands, a definitive court ruling on the ownership issue remains uncertain.

The broader implications of these legal disputes are significant but have yet to fully unfold, as the controversy reflects a deeper political and economic tension surrounding the ownership and distribution of mining and petroleum benefits. The Bougainville conflict, which led to the indefinite closure of the Bougainville Copper Mine at Panguna, is a textbook example. This conflict was driven in part by landowners' dissatisfaction with the distribution of profits and their claims to ownership of the minerals on their land.

The outcome of these legal battles will have profound effects on future mineral and petroleum projects in PNG. A judicial decision affirming customary landowners' rights to subsurface resources could lead to significant changes in the legal framework governing mineral ownership and benefit distribution.