The information will be used to calculate average passenger weights - useful for pilots when working out both the weight and balance of aircraft.

Those choosing to take part will be helping the airline to fly safely, an official said.

Passengers who volunteer for the scheme will be weighed before certain Air New Zealand flights departing from Auckland International Airport until 2 July, news.com.au reported.

Alastair James, Air New Zealand's load control improvement specialist, assured passengers their weight would not be displayed for others to see.

"We weigh everything that goes on the aircraft - from the cargo, to the meals, to the luggage in the hold," he said.

"For customers, crew and cabin bags, we use average weights, which we get from doing this survey."

He was quoted by Sky News Australia as saying: "It's important because we need to know the weight of everything that goes on our aircraft."

Mr James reassured passengers that weight information would be captured privately on a computer screen and would not appear in front of other travellers.

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While the study will focus on international passengers, the airline weighed domestic passengers in 2021.

"We know stepping on the scales can be daunting," Mr James said.

"We want to reassure our customers there is no visible display anywhere. No one can see your weight - not even us. It's completely anonymous.

"It's simple, it's voluntary, and by weighing in, you'll be helping us to fly you safely and efficiently, every time."

Air New Zealand said it needed at least 10,000 passengers to participate and the survey was a Civil Aviation Authority requirement, news.com.au reported.