The barrister and solicitor was sworn in as a Disputes Tribunal referee last week, taking his oath before Judge Stephen O'Driscoll in Alexandra.
Mr Cadogan has been appointed for a three-year term and is the only referee covering Queenstown and Central Otago.
He will continue his own legal practice, which focuses on criminal and family law.
"I don't really do civil work, so there's less chance of a conflict of interest."
Mr Cadogan, who is also a Vincent Community Board member, described his new role as referee as "another of life's challenges".
The Disputes Tribunal deals with a wide range of civil disputes, involving claims of up to $15,000, or up to $20,000 if both parties agree.
Hearings are less formal than court hearings and rulings made by the tribunal referees are binding, and can be enforced by the courts.
Mr Cadogan completed several days of training for the role and has received a warrant, signed by the Governor-General.
His first sitting is likely to be later this month.
Judge O'Driscoll said the work would be interesting.
"The Disputes Tribunal carries out an important function and means that work is diverted to the tribunal instead of coming before the district court," Judge O'Driscoll said.
Mr Cadogan replaces Maree Cowan, of Queenstown, who resigned from the role in November.
