Peter was admitted to the Bar in 1959. He was a partner in an Auckland law firm from 1961 to 1974 when he commenced practice as a Barrister. He was appointed Queens Counsel in 1983. While at the bar he took the LEADR course and qualified as a Mediator. In practice he acted as Counsel in major environmental and commercial cases as well as a mediator and arbitrator.
He was a Judge of the High Court from 1996 to 2004. During this time he served as a Commercial List judge and from time to time as a Divisional member of the Court of Appeal.
After retirement from the Court he has practiced as an Arbitrator and Mediator and sits on Pacific Island Courts of Appeal.
In 2002 he was appointed to the Permanent Court of Arbitration expert panel of Arbitrators for arbitration of disputes relating to natural resources and the environment.
In 2007 he was appointed Chair of the Board of Enquiry into the National Policy Statement on Electricity Reticulation. Later that year he was appointed Chair of the Royal Commission into Auckland Governance.