The Apple Watch has seen more than 2.3 million pre-orders, new sales estimates suggest, according to Digital Spy.

KGI Securities analyst Ming-Chi Kuo claims that Apple's production history and the lack of availability at retail level hints at the number of units sold.

"We estimate production of Apple Watch around 2.3 million units in March to May," MacRumours quotes him as saying. "Mass production of Apple Watch began in March and will likely reach 2.3 million by end of May.

"Considering that most consumers who preordered will not get the device until June, we estimate global pre-orders of over 2.3 million units."

KGI estimates that the Sport edition of the wearable is the most popular, accounting for 85% of all sales, with the Apple Watch and Apple Watch Edition making up 15% and 1% respectively.

It was previously reported that the Apple Watch sold an estimated 957,000 units in the US on the day that pre-orders began.

The Apple Watch will be released on April 24, but customers will not be able to purchase the device at Apple Stores on this date due to supply limitations.

Staff will prompt buyers to complete their order online for the time being.