## Facts

- A child (Heath) was born in 1979 following a brief relationship between Lyon (mother) and Wilcox (biological father).
- Before the Child Support Act 1991, a court order required Wilcox to pay NZ$10 per week, which he paid.
- Lyon later married Arlidge (stepfather), who lived with Lyon and Heath, acted as a parent figure, and had substantial income supporting the household.
- After the Child Support Act 1991 introduced a formula-based administrative regime, Lyon sought a formula assessment.
- The Commissioner assessed Wilcox’s liability at about NZ$676 per month, without considering the stepfather’s income.
- Wilcox sought a statutory “departure” (downward variation), arguing the child’s household was materially supported by the stepfather and it would be unjust to ignore that support.
- The Family Court refused departure, reasoning the stepfather had no statutory duty to support the child.
- The High Court reduced Wilcox’s liability by roughly half, relying in part on the stepfather’s contributions and a supposed “moral duty” to support the child.
- Lyon appealed to the Court of Appeal.

## Issues

1. Whether a step-parent’s income and household contributions may be considered in determining a departure from a statutory child-support formula assessment.
2. Whether a court may reduce a biological parent’s statutory child-support liability based on a step-parent’s “moral duty” or voluntary support.
3. What limits the Child Support Act 1991 places on judicial departures from the formula assessment in blended-family situations.

## Decision

- The Court of Appeal allowed Lyon’s appeal.
- It held the High Court erred by treating the stepfather’s income and alleged moral duty as grounds to reduce the biological father’s statutory liability.
- The Court restored (or substantially restored) the Commissioner’s formula assessment.

## Legal Principles

- The Child Support Act 1991 imposes enforceable child-support obligations on persons defined by the Act as liable parents; non-parents are not made liable absent express statutory provision.
- Departure from the formula assessment is constrained and cannot be used to reallocate responsibility from a liable parent to a non-liable step-parent by treating step-parent income as effectively available for assessment.
- A step-parent’s voluntary support or “moral duty” does not provide a lawful basis to reduce a biological parent’s statutory child-support liability.
- Treating step-parent income as a basis for lowering the liable parent’s payment is inconsistent with a formula-based administrative scheme intended to produce predictable, rule-based outcomes.

## Conclusion

The Court of Appeal held that, under the statutory child-support regime, a supportive step-parent’s resources and purported moral responsibilities cannot be used to reduce the legally enforceable child-support obligations of a biological parent determined by the statutory formula, except where the Act expressly permits departure on relevant grounds.


Lyon v. Wilcox, [1994] N.Z.F.L.R. 422 (N.Z. C.A. 1994)