Belgrave joined the public service in 1964, joining the Department of Trade and Industry. Belgrave was posted to London, where he served as second secretary at the High Commission for four years. Belgrave was promoted rapidly, and became Consul-General and Trade Commissioner in Melbourne in 1968. In 1973, Belgrave became Director of the Price and Stabilisation department in the Department of Trade and Industry, a key role responsible for monitoring commercial price controls in the then highly regulated New Zealand economy. In 1976, Belgrave was posted to Tokyo as Minister and Senior Trade Commissioner, where he served for four years. In 1980, he was assistant secretary of Trade and Industry, moving to Assistant Director-General in the Ministry of Agriculture and Fisheries in 1982.
Senior public servant
In 1985, Belgrave accepted his first of four postings as chief executive of a government department, as Comptroller of Customs. Belgrave left the public service in 1988 to become Chief Executive of the Bankers' Association, before being wooed back in 1989 by State Services CommissionerDon Hunn as Secretary of Commerce, the successor department of the Department of Trade and Industry. During this time, the departmental responsibilities included competition policy, energy, consumer affairs, company regulation, tourism, information technology policy, minerals, and economic development. In 1994, Belgrave was appointed by Hunn again as Secretary of Justice. Belgrave's mandate included the division of the Department of Justice into a separate policy unit, the Ministry of Justice, and the separate departments of Courts and Corrections. Belgrave retained responsibility for the Ministry of Justice, while the Departments for Courts and Corrections were established into separate structures. As Secretary of Justice, Belgrave was a member of the Electoral Commission. In 1997, Belgrave left the public sector again, to the post of executive director of the Electricity Supply Association, where he was responsible for the implementation and reorganisation of the energy sector, during Max Bradford's reforms of the electricity industry. In 1999, Belgrave became Chairman of the Commerce Commission, holding that post for two terms, before being appointed as Chief Ombudsman in 2003. Belgrave was chairman of the board of Victoria University's Institute of Policy Studies, and was a fellow of the Institute of Management, and the Institute of Directors.
Chief Ombudsman
Belgrave was involved in several high-profile inquiries in his role as Chief Ombudsman. In 2005, Belgrave ordered that the Minister of FinanceMichael Cullen must release the costings of the interest-free student loan policy prior to the election, after Cullen had refused to do so. In 2005, Belgrave, a former Justice Secretary, reviewed prisoner conditions at several prisons in New Zealand, following complaints about the prisoner treatment regime in prisons. In 2007, Belgrave conducted an inquiry into the Department of Corrections' policy for transporting prisoners, following the murder of 17-year-old Liam Ashley while being transported to Court in the back of a Corrections-contracted van. Belgrave described the Corrections' policy of transporting prisoners as "inhumane", and ordered a review of the prisoner transport system. Belgrave died in office in December 2007.