Wilson Harle has well-recognised expertise in the area of public and regulatory law. It was appointed in the area of Public Law to the first All of Government External Legal Services panel in 2011 and has remained on the panel since.

The firm acts as external counsel to a quasi-judicial body, the Gambling Commission, and as the external legal adviser on public law issues to a number of District Health Boards. It frequently acts for clients who operate in heavily regulated business environments in advising on and challenging regulatory decision making.

Examples of cases in which the firm has been engaged include:

• Acted for the Gambling Commission in declaratory proceedings (and a subsequent appeal) concerning the meaning of key provisions relating to the regulation of casinos in the Gambling Act 2003.
• Acted for the Auckland region district health boards in defending challenges, both at trial and on appeal, to a decision to award a long term contract for diagnostic laboratory services. The appeal decision is one of the leading cases on the reviewability of government procurement and the firm has since acted on several similar challenges in different areas throughout the country.
• Acted for the successful appellant in an appeal to the Supreme Court on the construction of provisions of the Adoption Act 1950 and the Status of Children Act 1969.
• Acted for a manufacturer in defending a Fair Trading Act prosecution for marketing statements relating to the environmental friendliness of its oxo-degradable plastic bags.
• Acted in the first successful defense of a test case prosecution by the Commerce Commission under consumer credit legislation (and upheld the acquittal on appeal) involving the interpretation and application of provisions relating to the early repayment of loans.
• Acted for defendants in air cargo price fixing proceedings brought by the Commerce Commission
• Acted for two directors of Capital + Merchant Finance in defending charges brought by the Serious Fraud Office and the Securities Commission following the collapse of the finance company owing substantial sums to debenture holders. 
• Acted for Vodafone (including on appeal to the Supreme Court) in successfully reviewing two decisions of the Commerce Commission for error of law (in conjunction with error of law appeals under the Telecommunications Act) relating to ongoing annual assessments of the amounts payable by the industry as compensation for the provision of universal service by the incumbent fixed network operator, Telecom, with a financial value well in excess of $100m
• Acted for an international engineering and environmental consultancy in relation to a series of appeals arising from an accidental pollution event.
• Acted for the Gambling Commission in a judicial review appeal to resolve issues about the interpretation of the licence suspension provisions of the Gambling Act.
• Acted for Vodafone in successfully defending an injunction brought by Telecom NZ to stop a Vodafone advertising campaign that included a claim of superiority of Vodafone’s network performance over its competitors
• Acted for the Gambling Commission in defending a challenge brought against the Commission and two Ministers on the setting of gambling levies which are paid by all licensed gambling operatives.
• Acted for the Canterbury Medical Officer of Health in a test case appeal (in which the major supermarket chains were represented) to the High Court and then the Court of Appeal regarding the interpretation and application of Single Alcohol Area licensing requirements which control how alcohol may be displayed and sold in supermarkets and grocery stores.
• Acted for a supplier of consumer goods in relation to charges alleging misleading country of origin claims.
• Acted for Vodafone in defending prosecutions brought by the Commerce Commission for breaches of the Fair Trading Act.