The law of Papua New Guinea consists of the Constitution, ordinary statutes enacted by Parliament or adopted at independence from overseas (together with their pendant regulations) and judge-made law.
Constitution
The Constitution is "autochthonous" (a constitutional term of art also used in Malaysia and meaning, literally, "aboriginal," indicating that legal continuity with the former metropolitan power was severed and the Constitution enacted by a constitutional convention of the newly independent state — as in the US after the American Revolution — rather than by an imperial parliament as in the case of the Constitutions of Canada and Australia). It is "entrenched," meaning that its provisions overbear any ordinary statutory enactments which the courts find to be inconsistent with it, in accordance with the constitutional authority of Marbury v. Madison, the case which established the principle of judicial review in the USA, the first modern state to have an entrenched constitution.
The Constitution contains a select number of human rights:
the right to life, liberty and security of person and protection of the law
the right to take part in political activities
freedom from inhuman treatment and forced labour
freedom of conscience, expression, information, assembly and association
freedom of employment and movement
the right to privacy and property
During the period of self-government from 1973 to 1975 during which the Constitution was drafted and arrangements for full sovereignty were made it was contemplated that as with most former colonies and trust territories in the British Commonwealth Papua New Guinea would wish to have its own indigenous head of state, and the Constitution specifically refers to the "Head of State" rather than to the King or the Crown. In the event, PNG chose to retain the monarchy and there have been no serious moves to alter that arrangement. In practice, the governor-general, chosen by free vote of sitting members of parliament, functions as a de facto non-executive president. Criminal proceedings are brought in the name of "The State" rather than "The King" or "R."; the King's effigy does not appear on banknotes or coins; apart from a few institutions having a royal warrant, such as the Royal Papua New Guinea Constabulary and the Royal Papua Yacht Club, the formal link with the monarchy is largely invisible, and there is little general awareness of it.
"Underlying law" The Constitution declares the "underlying law" — that is, the separate common law of Papua New Guinea — to consist of the Constitution, "customary law" derived from the "custom" of the various peoples of Papua New Guinea, and the common law of England as it stood at the date of Papua New Guinea's independence on 16 September 1975. That is to say, decisions of the High Court of Australia, the Judicial Committee of the Imperial Privy Council, not being part of the common law of England, and indeed of the pre-independence courts of Papua New Guinea itself are not part of Papua New Guinea law; but decisions of the House of Lords, the English Court of Appeal, the English King's Bench and other English courts up until Papua New Guinea's independence are.
The "customary law" portion of the "underlying law" was contemplated by the original framers of the Constitution as deriving from the regional customs of the country in the same way as the common law of England (that law which was "common" to the whole country) had done prior to 1189, deemed to be "time immemorial" in English law. In practice the courts have found great difficulty in applying traditional custom in a modern legal system and the development of the customary law according to indigenous Melanesian conceptions of justice and equity has been less thorough than may have been anticipated in 1975. In 2000 the National Parliament enacted the Underlying Law Act 2000 which purports to mandate greater attention by the courts to custom and the development of customary law as an important component of the underlying law. Thus far the statute appears not to have effected such a result.
Statutes
Statute law is very largely adopted from overseas jurisdictions. For example, the Criminal Code is adopted from Queensland; the Rules of Court are those of New South Wales; the Matrimonial Causes Act is the extremely old English statute of 1857 which had been in force in the Australian States before the federal Divorce Act, 1964; the Companies Act ch 146 was substantially the English Companies Act 1948; it was replaced by the Companies Act, 1997, adopted from New Zealand.