Industry sources reportedly told Digitimes that "order momentum for touch panels and other components has been weak".
The report also claimed that the situation is getting worse due to Donald Trump's recent move to impose heavy tariffs on China.
Apple has reportedly been preparing the 2019 iPhone ranges' production since July, so it appears unlikely that the company plans a significant production increase ahead of the smartphones' launch.
Apple is planning to launch three iPhones this year, which will serve as direct replacements for the iPhone Xs Max, Xs, and Xr.
Expected changes include a next-generation processor, improved cameras, and a new Taptic Engine to replace the current 3D touch system on the top two 2019 smartphones.