Apple told suppliers it could reduce the accuracy of the facial recognition technology in the upcoming iPhone X in order to speed up production of the devices, Bloomberg reported on Wednesday.

It's been widely-noted that Apple's $999 iPhone X will be in short supply when preorders open on Friday. Well-known Apple analyst Ming-Chi Kuo from KGI said there will be no more than 3 million iPhone X units available for purchase when preorders open.

At the heart of the delays is the 3-D sensor that recognizes faces and unlocks the handset. The feature is known as FaceID.

Despite the complexity of the sensor, Apple still gave suppliers its typical two-year lead time to develop it, according to Bloomberg. The tight schedule "underestimated the complexity" of making and assembling the components, the news agency said, citing people familiar with the matter.

Apple declined to comment when contacted by CNBC. The issue is with one of the components that make the FaceID technology work called the dot projector, which is key in determining whether to unlock the iPhone X based on a person's face. Suppliers struggled to combine the small and fragile components to create the dot projector, which slowed down production.

It's unclear how much of a difference the reduced specifications of FaceID could affect its performance on the iPhone X.