For many centuries, the Anglo-American tradition has emphasized the fiduciary duty of all those who manage other people’s assets and affairs, such as trustees and directors. This fiduciary duty imposes a higher duty of care on such people, than on the ordinary person.
While fiduciary duty is normally associated with relationships between directors and trustees, and those they represent, the duty extends to politicians and bureaucrats in that the common law has assumed that these agents act as trustees representing the interests of those they represent and whose taxes they collect and spend. As Wikepedia explains:
The fiduciary duty is a legal relationship between two or more parties (most commonly a “fiduciary” or “trustee” and a “principal” or “beneficiary”) that in English common law is arguably the most important concept within the portion of the legal system known as equity. Since the Judicature Acts merged the courts of Equity (historically based in England’s Court of Chancery) with the courts of common law, the concept of fiduciary duty also became usable in common law courts.
A fiduciary duty is the highest standard of care imposed at either equity or law. A fiduciary is expected to be extremely loyal to the person they owe the duty (the principal”): they must not put their personal interests before the duty, and must not profit from their position as a fiduciary, unless the principal consents. The fiduciary relationship is highlighted by good faith, loyalty and trust, and the word itself originally comes from the Latin fides, meaning faith, and fiducia.
However, the concept of extending the fiduciary duty to the public realm has never been emphasized in New Zealand, and generally the courts have been reluctant to allow it to be introduced into argument in cases involving the relationship between the citizen and the state.