Add stepping on some scales to the preflight routine.

New Zealand's national airline is asking passengers to weigh in after checking in for international flights from Auckland International Airport.

Air New Zealand wants to weigh 10,000 passengers during the monthlong survey. But the numbers won't be flashing up on scales for all to see, it promised, and will remain anonymous even to staff.

It's all part of a requirement by the Civil Aviation Authority, the country's industry watchdog, to help calculate the weight and balance of planes before takeoff.

“It’s a regulatory requirement for us to know the weight of everything that goes on the aircraft and there’s a good reason for that,” said Alastair James, the airline’s load control improvement specialist.

"To fly safely and efficiently, we need to be able to calculate the weight and balance of the aircraft each and every time we fly," he said.

James added that passengers "have nothing to worry about. There’s no weight shown on the screen, anywhere, it’s just captured and goes straight into the computer."

They will also separately place their luggage on a scale for weighing.

This is not the first time the airline is asking passengers to do so, with customers on domestic flights asked to weigh in a couple of years ago.

While the survey has largely received support in New Zealand, some U.S. citizens expressed their concerns about privacy and body discrimination on social media.

John Cox, NBC News aviation expert, said the methods and data collected by Air New Zealand are important and could bring "wide-ranging benefits" to the world.

"Air New Zealand and the New Zealand regulators are in fact helping the industry ... I think you may see some other airlines utilize this at some point in the future."