They met for the first time in Wellington last week.
"The Inspector-General stands in the shoes of the public: we try to ask what the public would ask," Gwyn said in a statement.
"My office is relatively small, and the great breadth and diversity of experience among the members of the reference group will help us better ensure New Zealand's intelligence and security agencies act lawfully and properly."
The Inspector-General scrutinises whether New Zealand's intelligence and security agencies (the NZSIS and the GCSB) act lawfully and also whether reasonable New Zealanders would think their conduct was "right", or proper.
Hager said he would assume that Gwyn had appointed him because of his knowledge of the intelligence agencies and his work in holding them to account.
List of members:
Ben Creet - Issues manager, Internet NZ
Professor Rouben Azizian - Director, Centre for Defence and Security Studies, Massey University
Dr Nicole Moreham - Associate Professor, Faculty of Law, Victoria University of Wellington
Dr Paul Buchanan - Director, 36th Parallel Assessments
David Fisher - Journalist, New Zealand Herald
John Ip - Senior Lecturer, Assistant Dean (Academic), Faculty of Law, University of Auckland
Nicky Hager - Journalist, author
Thomas Beagle - Chairman, NZ Council for Civil Liberties
Treasa Dunworth - Associate Professor, Public International Law, University of Auckland
Suzanne Snively - Chair, Transparency International
Deborah Manning – Barrister