Chinese company GoerTek, one of Apple's key manufacturers, would begin testing the manufacturing processes for the newest generation of AirPods at its audio factory in northern Vietnam, Nikkei Asian Review quoted two sources with knowledge of the plan as saying.

This will be the first time it produced outside China since its introduction in 2016. Apple has written to components suppliers, asking them to support Goertek's efforts though initially volumes will be very small.

"Suppliers are requested to keep the pricing unchanged for the trial production stage, but this can be reviewed once volumes are increased," one of the sources with direct knowledge of the communication said. 

"The initial output will be limited, but it is easy to increase capacity once all the manufacturing procedures are running smoothly."

GoerTek in October last year asked all suppliers involved in its AirPods production to ship all necessary materials to Vietnam. Taiwanese iPhone assembler Foxconn, another major Apple supplier, has leased space in an industrial park in northern Vietnam.