He served as Chief Justice of the Cook Islands, a judge of the High Court of New Zealand, and as Inspector-General of Intelligence and Security.
[1][2] He studied law at the University of Otago, then worked for Crown solicitors for five years before joining Bell Gully as a commercial lawyer.
[5] As Inspector-General, Greig investigated the actions of the New Zealand Security Intelligence Service in burgling the home of anti-free-trade activist Aziz Choudry and found them to be "lawful, reasonable and justified".
[6] In 2003, while he was responsible for reviewing the security risk certificate against Algerian refugee Ahmed Zaoui he gave an interview to the New Zealand Listener in which he said that if it were up to him, Zaoui would be "outski" on the next plane and that "we don't want lots of people coming in on false passports thrown down the loo on the plane, saying, 'I'm a refugee, keep me here'.
"[7] In March 2004 he resigned[8] after the High Court found that he had displayed apparent bias and disqualified him from the Zaoui case.