The Collaborative International Dictionary
Postmaster-general \Post"mas`ter-gen"er*al\, n.; pl. Postmasters-general. The chief officer of the post-office department of a government. In the United States the postmaster-general is a member of the cabinet.
Wikipedia
The Postmaster-General in New Zealand was the government minister responsible for the New Zealand Post Office from 1858 to 1989, when the NZPO (formerly the P&T or Post and Telegraph Department) was split into three SOEs responsible to the Minister of State Owned Enterprises: New Zealand Post Limited, Telecom New Zealand Limited, and Post Office Bank Limited.
Usage examples of "postmaster-general".
The postmaster-general was also authorized to forbid the payment of postal money orders to persons engaged in fraudulent lotteries, gift enterprises, and other schemes for swindling the public, and to instruct postmasters to return to the writers, with the word "fraudulent" written or stamped on the outside, all registered letters directed to such persons or firms.