Apple reportedly has asked its suppliers to expand output of its next iPhone, due out in September, by as much as 20 per cent.

Suppliers will boost output from 70 to 80 million for the iPhone 6 models, a record production run last year, to 85 million to 90 million by the end of the year for the new model, according to the Wall Street Journal.

Bloomberg reported last week that Apple has started early production of devices, which feature a screen including the “Force Touch” technology introduced by Apple’s Watch.

Force Touch enables the device to differentiate between “a tap and a press”, enabling users to access different functions based on the intensity of the input.

The new lineup will have the same screen sizes as the iPhone 6 and 6 Plus — 4.7- and 5.5-inch.

The Journal said Apple is considering using Taiwan-based Wintron as its third assembler.

Last week DigiTimes said component suppliers in Taiwan have started deliveries to Apple’s existing OEMs — Foxconn and Pegatron — for production of the next-generation device.

The expanded output is to keep up with soaring demand in China, which has been Apple’s main growth market. Unit sales of the iPhone jumped 46 per cent between March and May in China, according to Kantar Worldpanel.

That comes after Apple reported its revenue in greater China expanded 71 per cent to $16.8 billion in Q1, accounting for 56 per cent of total revenue growth in the quarter.

With Apple planning to increase the number of retail stores in China from 15 to 40 over the next two years, it is expecting continued strong growth for some time.