Foxconn Technology Group, which supplies Apple with components for the iPhone, is reportedly planning to cut costs by billions of pounds amid concerns that iPhone sales growth is slowing.

The Taiwanese manufacturer will slash 20bn yuan (£2.3bn) from expenses in 2019, Bloomberg News reported.

Foxconn faces “a very difficult and competitive year”, according to an internal memo. The company will need to reduce expenses in its iPhone operations by 6bn yuan next year, Bloomberg says.

The iPhone is a significant source of profits for the California-based Apple. Foxconn, which is owned by Hon Hai Precision Industry, plans to cut one in 10 non-technical staff and conduct a review of employees earning more than $150,000 (£120,000) a year, the report says.

Foxconn, which also supplies parts to other large technology companies such as Google and Amazon, made revenues of £3.7bn in 2017. However, it has faced criticism for its working practices, including an increasing reliance on a disposable workforce.

Apple has been at the heart of a recent sell-off on US stock markets that led to billions of dollars being wiped from the value of Wall Street’s biggest listed companies.

Apple shares rose by about 0.4% in morning trading in New York on Wednesday, after losing more than 20% since hitting a record high at the start of October – making it a trillion-dollar company.

At least four suppliers to Apple have recently cut revenue forecasts, citing a drop in orders from large customers. Foxconn reported lower-than-expected profits in the third quarter of the year.

Japanese media have also reported that Apple has scaled back its orders for its lower-cost iPhone XR, for which Foxconn is a major assembler.

A spokesperson for Foxconn said: “We regularly review our global operations. The review being carried out by our team this year is no different than similar exercises carried out in past years to ensure that we enter into each new year with teams and budgets that are aligned with the current and anticipated needs of our customers, our global operations and the market and economic challenges of the next year or two.”