Lining the glass display cases of Shenzhen's giant tech malls, knockoff versions of Apple Inc's smartwatch were on sale at many stalls, with some Chinese consumers eager to snap them up for a fraction of the cost of the original.

"It came on sale in mid-March and has been constantly out of stock," said one imitation-Apple Watch seller who declined to give his name. "On average we sell around 40 a day. Some customers just came and bought five or more at a time."

The watches, built on Google Inc's operating system, do not need a separate smartphone to work, said one merchant. At her store, one was retailing for 360 yuan ($58) — around one eighth of the cost of Apple's cheaper Watch models.