A legal complaint has been filed in California on December 30 by Miami residents Paul Orshan and Christopher Endara stating that the 16GB iPhones and iPads that they purchased was offering less usable storage space than was promised.

The space was further reduced when the iPhone 5S was upgraded from iOS 7 to iOS 8, according to reports.

Silicon Beat reports that the lawsuit alleges that Apple "doesn't inform users just how much storage its new operating system will eat up." The complainant also alleged Apple pushed users to buy more cloud storage via its own iCloud service.

"In addition to making material misrepresentations and omissions to prospective purchasers of Devices with iOS 8 pre-installed, Apple also makes misrepresentations and omissions to owners of Devices with predecessor operating systems," according to the complaint.

"These misrepresentations and omissions cause these consumers to 'upgrade' their Devices from iOS 7 (or other operating systems) to iOS 8," it said.

"Apple fails to disclose that upgrading from iOS 7 to iOS 8 will cost a Device user between 600 MB and 1.3 GB of storage space - a result that no consumer could reasonably anticipate," it added.