"We've officially landed in Auckland," the airline tweeted as flight QR920 landed at 7.25am (1825 GMT Sunday), five minutes ahead of schedule after a 16 hour 23 minute flight.
The long-range Boeing 777-200LR crossed 10 time zones on its marathon flight.
Qatar Airways noted the flight was longer than the entire "Lord of the Rings" and "The Hobbit" trilogies which were filmed in New Zealand.
There were four pilots on board as well as 15 cabin crew who served 1,100 cups of tea and coffee, 2,000 cold drinks and 1,036 meals during the flight.
In keeping with international tradition to welcome inaugural flights, the Auckland airport rescue service showered the plane with water cannons on arrival.
New Zealand Trade Minister Todd McClay said the estimated economic impact of the new service "will be well in excess" of NZ$50 million (US$36 million) with the increased freight capacity provided.
In March last year, Emirates airline launched what was then thought to be the world's longest non-stop scheduled commercial flight, with a service from Dubai to Auckland, spanning 14,200 kilometres (8,824 miles).
Air India's Delhi-San Francisco flight claims the world's longest by flying distance but when measured on the surface of the earth Doha and Auckland are further apart.
