Section 18(1) of the Marriage Act (Chapter 280) provides that the prohibited degrees are set out in Schedule 2. A marriage within them is void under section 17(1)(b).
Schedule 2.1 — the marriage of a man is prohibited if the woman is, or has been, his
| Consanguinity — blood | Affinity — by marriage |
|---|---|
| Ancestress | Wife’s mother |
| Descendant | Wife’s grandmother |
| Sister | Wife’s daughter |
| Father’s sister | Wife’s son’s daughter |
| Mother’s sister | Wife’s daughter’s daughter |
| Brother’s daughter | Father’s wife |
| Sister’s daughter | Grandfather’s wife |
| — | Son’s wife |
| — | Son’s son’s wife |
| — | Daughter’s son’s wife |
Schedule 2.2 — the marriage of a woman is prohibited if the man is, or has been, her
| Consanguinity — blood | Affinity — by marriage |
|---|---|
| Ancestor | Husband’s father |
| Descendant | Husband’s grandfather |
| Brother | Husband’s son |
| Father’s brother | Husband’s son’s son |
| Mother’s brother | Husband’s daughter’s son |
| Brother’s son | Mother’s husband |
| Sister’s son | Grandmother’s husband |
| — | Daughter’s husband |
| — | Son’s daughter’s husband |
| — | Daughter’s daughter’s husband |
Schedule 2.2 is the exact counterpart of Schedule 2.1. The prohibitions are symmetrical.
Consanguinity covers the direct line in both directions — ancestors and descendants, without limit — plus siblings, aunts and uncles, and nieces and nephews.
Affinity covers the equivalent relationships created by a marriage: parents-in-law and their ascendants, step-children and their descendants, step-parents and their ascendants, and children-in-law and their descendants.
Neither list includes a father’s brother’s child, a mother’s sister’s child, or any other cousin. The prohibitions stop at aunts, uncles, nieces and nephews.
Note also that the affinity prohibitions use the words “is, or has been”. So they continue to apply after the marriage that created the relationship has ended by death or divorce — a man may not marry his former wife’s mother.
That is precisely the situation section 20 addresses, by allowing a Judge to permit a marriage within the prohibited degrees of affinity in exceptional circumstances.
Schedule 2.3 — kinds of relationship
For the purposes of this Schedule, it is immaterial whether the relationship is of the whole blood or half-blood, or whether it is traced through, or to, a person of illegitimate birth.
So a half-sister is within the prohibition as fully as a full sister, and a relationship traced through a child born outside marriage counts. The Schedule looks to the actual blood relationship, not to legal status.
Relationships created by adoption
Section 19 extends Schedule 2 so that a relationship of consanguinity includes a relationship traced through, or to, a person who is or was an adopted child, and deems the relationship between an adopted child and each adoptive parent to be the natural relationship of child and parent.
Section 21 then allows a Judge to permit a marriage within the prohibited degrees arising only from section 19 — except where the relationship so created is parent and child or brother and sister.
Where the prohibited degrees apply
Sections 17, 18 and 20 relating to the prohibited degrees, and Schedule 2, apply to marriages in the country, other than marriages to which Division V.3 applies, wherever the parties are domiciled or intend to make their home.
Domicile is irrelevant for a marriage here. Two foreign nationals marrying in Papua New Guinea are subject to Schedule 2, whatever their home law permits.
Section 24(2) preserves the ordinary common law rules of private international law for a marriage taking place outside the country, other than one under Part V of the Marriage Act 1961 of Australia. See foreign marriages.
A marriage solemnized before the commencement date is not voidable on the ground of consanguinity or affinity unless the parties were, at the time of the marriage, within one of the degrees set out in Schedule 2 — and subsection (3) makes clear that this does not make voidable a marriage that would not otherwise be so.
See marriages before the Act and section 23.
Solemnising a marriage where the celebrant knows of a legal impediment is an offence under section 63.
Sources
- Marriage Act (Chapter 280) — ss 17–24, 63, Schedule 2
Before relying on anything here, read the current text of the Marriage Act (Chapter 280) and check for later amendments. If a decision matters to you, get advice — start with the Office of the Public Solicitor, or find a firm in the law firms directory.