Apple is estimated to have shipped over four million smartwatches in Q2, more than any other wearable vendors.

An analyst said the company has sold more wearable solutions than Fitbit, Xiaomi and all other smartwatch vendors in Q2, despite its iWatch price being higher than competitors’ ranges.

The analyst at Canalys added that early iWatch sales were affected by Apple missing the Q4 2014 holiday season and constraints in shipment supplies after launch.

Chris Jones, VP at Canalys, said: "Improvements in performance, battery life and sensor integration are needed to make future models more attractive, but it is the quality of third-party apps that will determine whether the Apple Watch will be a long-term success."

The firm also forecast Apple to ship 20 million devices by the end of 2015. Apple’s Q2 results will be announced later today.