Peter appeared periodically in the Maori Land Court in the 1980s and 1990s on a variety of matters. Peter was Counsel in the High Court proceedings (Te Rununga o Ngai Tahu v Waitangi Tribunal [2002] 2 NZLR 179) which involved a challenge to the exercise of the jurisdiction of the Maori Land Court under section 6A of the Waitangi Tribunal Act. Peter was also counsel in the subsequent Court of Appeal hearing in the same matter.

Since 2000 Peter has appeared regularly before the Waitangi Tribunal as Counsel for various iwi. Most of the appearances have related to the Northern South Island inquiry. Peter has also been briefed to appear in inquiries relating to the Wellington and Central North Island areas. 

Over the years Peter has appeared before various Tribunals such as the Transport Licensing Authority and administrative bodies such as the Accident Compensation Appeal Authority.  One reported decision is re Adam decision number 47/88 Accident Compensation Appeal Authority [1988] 7 NZAR 131. 

Throughout the 1990s Peter appeared regularly in the Employment Tribunal with over 100 of those decisions being reported either in the Employment Reports of New Zealand or the Employment Head Notes of New Zealand. He also continues to appear regularly in the Employment Relations Authority, principally for employers, with many of those decisions being reported or noted.